Unwrapped 2D view of a stimulation lead with complex electrode array geometry

ABSTRACT

The disclosure is directed to programming implantable stimulators to deliver stimulation energy via one or more implantable leads having complex electrode array geometries. The disclosure also contemplates guided programming to select electrode combinations and parameter values to support efficacy. The techniques may be applied to a programming interface associated with a clinician programmer, a patient programmer, or both. A user interface permits a user to view electrodes from different perspectives relative to the lead. For example, the user interface provides a side view of a lead and a cross-sectional view of the lead. The user interface may include an axial control medium to select and/or view electrodes at different axial positions along the length of a lead, and a rotational control medium to select and/or view electrodes at different angular positions around a circumference of the lead.

This application is a continuation of U.S. patent application Ser. No.13/592,918, filed Aug. 23, 2012, which is a continuation of U.S. patentapplication Ser. No. 11/591,188, filed Oct. 31, 2006 and issued as U.S.Pat. No. 8,380,321 on Feb. 19, 2013, which claims the benefit of U.S.Provisional Patent Application No. 60/776,454, filed Feb. 24, 2006, andU.S. Provisional Patent Application No. 60/785,181, filed Mar. 23, 2006.The entire contents of application Ser. Nos. 13/592,918, 11/591,188,60/776,454, and 60/785,181 are incorporated herein by reference.

TECHNICAL FIELD

The invention relates to electrical stimulation therapy and, moreparticularly, to selection of electrode combinations for delivery ofstimulation therapy to a patient.

BACKGROUND

Implantable electrical stimulators may be used to deliver electricalstimulation therapy to patients to treat a variety of symptoms orconditions such as chronic pain, tremor, Parkinson's disease, epilepsy,urinary or fecal incontinence, sexual dysfunction, obesity, orgastroparesis. In general, an implantable stimulator deliversneurostimulation therapy in the form of electrical pulses. Animplantable stimulator may deliver neurostimulation therapy via one ormore leads that include electrodes located proximate to target locationsassociated with the brain, the spinal cord, pelvic nerves, peripheralnerves, or the stomach of a patient. Hence, stimulation may be used indifferent therapeutic applications, such as deep brain stimulation(DBS), spinal cord stimulation (SCS), pelvic stimulation, gastricstimulation, or peripheral nerve stimulation. Stimulation also may beused for muscle stimulation, e.g., functional electrical stimulation(FES) to promote muscle movement or prevent atrophy.

In general, a physician selects values for a number of programmableparameters in order to define the electrical stimulation therapy to bedelivered by the implantable stimulator to a patient. For example, thephysician ordinarily selects a combination of electrodes carried by oneor more implantable leads, and assigns polarities to the selectedelectrodes. In addition, the physician selects an amplitude, which maybe a current or voltage amplitude, a pulse width and a pulse rate forstimulation pulses to be delivered to the patient. A group ofparameters, including electrode combination, electrode polarity,amplitude, pulse width and pulse rate, may be referred to as a programin the sense that they drive the neurostimulation therapy to bedelivered to the patient. In some applications, an implantablestimulator may deliver stimulation therapy according to multipleprograms either simultaneously or on a time-interleaved, overlapping ornon-overlapping, basis.

The process of selecting electrode combinations and other parameters canbe time consuming, and may require a great deal of trial and errorbefore a therapeutic program is discovered. The “best” program may be aprogram that best balances greater clinical efficacy and minimal sideeffects experienced by the patient. In addition, some programs mayconsume less power during therapy. The physician typically needs to testa large number of possible electrode combinations within the electrodeset implanted in the patient, in order to identify an optimalcombination of electrodes and associated polarities. As mentionedpreviously, an electrode combination is a selected subset of one or moreelectrodes located on one or more implantable leads coupled to animplantable neurostimulator. As a portion of the overall parameterselection process, the process of selecting electrodes and thepolarities of the electrodes can be particularly time-consuming andtedious.

The physician may test electrode combinations by manually specifyingcombinations based on intuition or some idiosyncratic methodology. Thephysician may then record notes on the efficacy and side effects of eachcombination after delivery of stimulation via that combination. In somecases, efficacy can be observed immediately within the clinic. Forexample, spinal cord stimulation may produce parasthesia and sideeffects that can be observed by the physician based on patient feedback.In other cases, side effects and efficacy may not be apparent until aprogram has been applied for an extended period of time, as is sometimesthe case in deep brain stimulation. Upon receipt of patient feedbackand/or observation of symptoms by the physician, the physician is ableto compare and select from the tested programs.

In order to improve the efficacy of neurostimulation therapy, electricalstimulators have grown in capability and complexity. Modernneurostimulators tend to have larger numbers of electrode combinations,larger parameter ranges, and the ability to simultaneously delivermultiple therapy configurations by interleaving stimulation pulses intime. Although these factors increase the physician's ability to adjusttherapy for a particular patient or disease state, the burden involvedin optimizing the device parameters has similarly increased.Unfortunately, fixed reimbursement schedules and scarce clinic timepresent challenges to effective programming of neurostimulator therapy.

Existing lead sets include axial leads carrying ring electrodes disposedat different axial positions, and so-called “paddle” leads carryingplanar arrays of electrodes. Selection of electrode combinations withinan axial lead, a paddle lead, or among two or more different leadspresents a challenge to the physician. The emergence of more complexelectrode array geometries presents still further challenges. The designof the user interface used to program the implantable neurostimulator,in the form of either a physician programmer or patient programmer, hasa great impact on the ability to efficiently define and selectefficacious stimulation programs.

SUMMARY

In general, the disclosure is directed to techniques for programmingimplantable stimulators to deliver stimulation energy via one or moreimplantable leads having complex electrode array geometries. Thetechniques may be applied to a programming interface associated with aclinician programmer, a patient programmer, or both. In addition, thedisclosure contemplates techniques for guided programming to selectelectrode combinations and parameter values to support therapeuticefficacy.

To select electrode combinations within a complex electrode arraygeometry, in accordance with this disclosure, a user interface permits auser to view electrodes from different perspectives relative to thelead. For example, the user interface may provide a side perspective ofa lead and a cross-sectional perspective of the lead. In addition, theuser interface may include an axial control medium to select and/or viewelectrodes at different positions along the length of a lead from theaxial perspective, and a rotational control medium to select and/or viewelectrodes at different angular positions around a circumference of thelead from the cross-sectional perspective.

A complex electrode array geometry generally refers to an arrangement ofstimulation electrodes at multiple non-planar or non-coaxial positions,in contrast to simple electrode array geometries in which the electrodesshare a common plane or a common axis. An example of a simple electrodearray geometry is an array of ring electrodes distributed at differentaxial positions along the length of a lead. Another example of a simpleelectrode array geometry is a planar array of electrodes on a paddlelead.

An example of a complex electrode array geometry, in accordance withthis disclosure, is an array of electrodes positioned at different axialpositions along the length of a lead, as well as at different angularpositions about the circumference of the lead. In some embodiments, theelectrodes in the complex array geometry may appear similar tonon-contiguous, arc-like segments of a conventional ring electrode. Alead with a complex electrode array geometry may include multiple ringsof electrode segments. Each ring is disposed at a different axialposition. Each electrode segment within a given ring is disposed at adifferent angular position. The lead may be cylindrical or have acircular cross-section of varying diameter. Another example of a complexelectrode array geometry is an array of electrodes positioned onmultiple planes or faces of a lead. As an illustration, arrays ofelectrodes may be positioned on opposite planes of a paddle lead ormultiple faces of a lead having a polygonal cross-section.

An electrode combination is a selected subset of one or more electrodeslocated on one or more implantable leads coupled to an implantablestimulator. The electrode combination also refers to the polarities ofthe electrodes in the selected subset. The electrode combination,electrode polarities, amplitude, pulse width and pulse rate togetherdefine a program for delivery of electrical stimulation therapy by animplantable stimulator via an implantable lead or leads.

A user interface that permits a user to view electrodes from differentperspectives relative to the lead and/or actuate both axial and rotationcontrol media to select or view electrodes on the lead can facilitateefficient evaluation, selection and programming of electrodecombinations and stimulation programs including the electrodecombinations. In some embodiments, the user interface may supportautomated guidance techniques that permit guided selection of electrodecombinations and parameters, e.g., pursuant to a predetermined ordynamically created sequence of electrode combinations to be evaluated.

The user interface also may present, on a selective basis, an electrodeview or a field view of the lead or leads. The electrode view or fieldview may present one or multiple perspectives such as side andcross-sectional perspectives of a lead. In the electrode view, the userselects individual electrodes to form an electrode combination, andspecifies parameters for stimulation delivered via the electrodecombination. In a field view, the user manipulates a representation ofan electrical stimulation field produced by a selected electrodecombination. For example, the user may change the size, shape orposition of the field using graphical input media such as cursor orstylus control.

For example, in the field view, the user may perform various fieldmanipulation operations such as a grow/shrink operation to expand orcontract the size of a field, a spread/focus operation to expand orcontract the number of electrodes included in an electrode combination,and a split/merge operation to divide a single electrode combinationinto multiple combinations or vice versa. In response to suchoperations, a programmer selects appropriate electrode combinations,polarities, amplitudes, pulse widths, and pulse rates sufficient tosupport the specified operation.

The techniques described herein may be used during a test or evaluationmode to select different electrode combinations in an effort to identifyefficacious electrode combinations. Additionally, the techniques may beused to select different electrode combinations associated withdifferent stimulation programs during an operational mode, eitherdirectly or by selection of programs including such electrodecombinations. For example, the techniques and associated user interfacesmay be implemented in a clinician programmer used by a clinician toprogram a stimulator, in a patient programmer used by a patient toprogram or control a stimulator, or in an external stimulator includingboth pulse generation and programming functionality.

In one embodiment, the disclosure provides a method that includespresenting on a display a side view of a representation of animplantable lead having a complex electrode array geometry, presentingon the display a cross-sectional view of the representation of the lead,and receiving user input via interaction with at least one of the sideview and the cross-sectional view defining stimulation for delivery by amedical device via the lead.

In another embodiment, the disclosure provides a programmer thatincludes a user interface and a processor that presents a side view of arepresentation of an implantable lead having a complex electrode arraygeometry via the user interface, presents a cross-sectional view of therepresentation of the lead via the user interface, and receives userinput via interaction with at least one of the side view and thecross-sectional view on the user interface defining stimulation fordelivery by a medical device via the lead.

In an additional embodiment, the disclosure provides a computer-readablemedium including instructions to cause a processor to present on adisplay a side view of a representation of an implantable lead having acomplex electrode array geometry, present on the display across-sectional view of the representation of the lead, and receive userinput specifying selection of electrodes on the lead via interactionwith at least one of the side view and the cross-sectional view.

The disclosure may provide one or more advantages. For example, the userinterface may represent the implanted lead as a side view and across-sectional view. Further, input media provided by the userinterface may allow a user to change the perspective in which the leadis view in multiple directions, e.g., axial and rotational. In thismanner, the user interface may be able to substantially completelyillustrate the electrodes on one or more leads, even in a lead with acomplex electrode array geometry. In some embodiments, the userinterface may transition between an electrode view of the lead thatpermits manual selection of electrodes, and a field view of the leadthat permits manipulation of a representation of a stimulation fieldproduced by the lead. The programmer may automatically adjust anelectrode combination and stimulation parameter values associated withthe lead to approximate the field manipulated by the user, e.g., in thefield view.

The details of one or more embodiments of the invention are set forth inthe accompanying drawings and the description below. Other features,objects, and advantages of the invention will be apparent from thedescription and drawings, and from the claims.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a conceptual diagram illustrating an example stimulationsystem with a stimulation lead implanted in the brain of a patient.

FIGS. 2A and 2B are conceptual diagrams illustrating two differentimplantable stimulation leads.

FIGS. 3A-3D are cross-sections of example stimulation leads having oneor more electrodes around the circumference of the lead.

FIG. 4 is a block diagram illustrating an example implantable stimulatorfor delivery of electrical stimulation therapy via one or more leadshaving a complex electrode array geometry.

FIG. 5 is a block diagram illustrating an example programmer forprogramming and controlling the implantable stimulator of FIG. 4.

FIGS. 6-21 are schematic diagrams illustrating example user interfacespresented by the programmer of FIG. 5.

FIGS. 22-25 are flow diagrams illustrating example operation of theprogrammer of FIG. 5.

FIG. 26 is a diagram illustrating ring-based selection of axialpositions on a lead having a complex electrode array geometry.

FIGS. 27A, 27B, 27C, 27D, 27E, and 27F and FIGS. 28A, 28B, 28C, 28D,28E, and 28F are diagrams illustrating selection of different electrodecombinations on a lead having a complex electrode array geometry.

FIG. 29 is a diagram illustrating a user interface presenting two sidesof a lead having a complex electrode array geometry.

FIGS. 30A, 30B, 30C, and 30D are conceptual diagrams of examplestimulation templates stored for electrode combinations.

FIGS. 31-36 are schematic diagrams and a flow diagram illustratingexample user interfaces that present stimulation templates to the user.

FIG. 37 is a flow diagram illustrating example operation of theprogrammer for selecting one or more stimulation templates.

FIGS. 38-44 are schematic diagrams illustrating example user interfacesthat present electrical field models and activation field models to theuser.

FIG. 45 is a flow diagram illustrating example operation of theprogrammer for generating and presenting an electrical field model.

FIG. 46 is a flow diagram illustrating example operation of theprogrammer for generating and presenting an activation field model.

FIG. 47 is a diagram illustrating a user interface presenting athree-dimensional electrode view of a lead having a complex electrodearray geometry.

FIG. 48 is a diagram illustrating a user interface presenting athree-dimensional field view of a lead having a complex electrode arraygeometry.

DETAILED DESCRIPTION

Electrical stimulation therapy may provide relief to a patient from manyconditions. However, the stimulation therapy efficacy is contingent on aphysician, or clinician, correctly configuring, or programming, thestimulation parameters in a manner that provides therapy to the patientwhile minimizing side-effects produced from the stimulation. Efficacymay be judged in terms of the extent to which therapy relieves symptomsor a disorder or disease, in combination with the absence of undesirableside effects. Due to physiological diversity, different disease states,and inaccuracies in stimulation lead placement, the parameters may varygreatly between patients. Therefore, the physician must individuallyprogram stimulation parameters for each patient. This programmingprocess may continue throughout the therapy as patient needs change.

Implanting stimulation leads with complex electrode array geometriesintroduces more complex programming challenges for the physician.Although leads with complex electrode array geometries provide greaterflexibility in defining a stimulation field to provide therapy, thephysician must identify effective electrodes, electrode polarity,current and voltage amplitudes, pulse widths, and pulse frequencies forelectrode combination at different axial and angular positions.Physicians may prefer to focus on stimulating a particular anatomicalstructure or target tissue of the patient, which becomes difficult whenfacing potentially millions of programming options presented by acomplex electrode array geometry.

A complex electrode array geometry generally refers to an arrangement ofstimulation electrodes at multiple non-planar or non-coaxial positions,in contrast to simple electrode array geometries in which the electrodesshare a common plane or a common axis. An example of a simple electrodearray geometry is an array of ring electrodes distributed at differentaxial positions along the length of a lead. Another example of a simpleelectrode array geometry is a planar array of electrodes on a paddlelead.

An example of a complex electrode array geometry, in accordance withthis disclosure, is an array of electrodes positioned at different axialpositions along the length of a lead, as well as at different angularpositions about the circumference of the lead. In some embodiments, theelectrodes in the complex array geometry may appear similar tonon-contiguous, arc-like segments of a conventional ring electrode. Alead with a complex electrode array geometry may include multiple ringsof electrode segments. Each ring is disposed at a different axialposition. Each electrode segment within a given ring is disposed at adifferent angular position. The lead may be cylindrical or have acircular cross-section of varying diameter.

Another example of a complex electrode array geometry is an array ofelectrodes positioned on multiple planes or faces of a lead. As anillustration, arrays of electrodes may be positioned on opposite planesof a paddle lead or multiple faces of a lead having a polygonalcross-section in a plane transverse to the longitudinal axis of thelead. As further examples, electrodes may be arranged at different axialand angular positions on leads defining spherical, hemispherical orgenerally rounded surfaces. Leads with complex electrode arraygeometries may have a defined shape or be at least partially conformableto an anatomical structure.

An electrode combination is a selected subset of one or more electrodeslocated on one or more implantable leads coupled to an implantablestimulator. The electrode combination also refers to the polarities ofthe electrode segments in the selected subset. The electrodecombination, electrode polarities, amplitude, pulse width and pulse ratetogether define a program for delivery of electrical stimulation therapyby an implantable stimulator via an implantable lead or leads. Byselecting particular electrode combinations, a physician can targetparticular anatomic structures. By selecting values for amplitude, pulsewidth and pulse rate, the physician can attempt to optimize theelectrical therapy delivered to the patient via the selected electrodecombination or combinations.

This disclosure is directed to techniques for programming implantablestimulators to deliver stimulation energy via one or more implantableleads having complex electrode array geometries. The techniques may beapplied to a programming interface associated with a physicianprogrammer, a patient programmer, or both. In addition, the disclosurecontemplates techniques for guided programming to select electrodecombinations and parameter values to support therapeutic efficacy. Forexample, the user interface may support automated guidance techniquesthat permit guided selection of electrode combinations and parameters,e.g., pursuant to a predetermined or dynamically created sequence ofelectrode combinations to be evaluated.

To select electrode combinations within a complex electrode arraygeometry, in accordance with this disclosure, a user interface permits auser to view electrodes from different perspectives relative to thelead. For example, the user interface may provide an axial perspectiveof a lead, and a cross-sectional perspective of the lead in a planetransverse to a longitudinal axis of the lead. In addition, the userinterface may include an axial control medium to select and/or viewelectrodes at different positions along the length of a lead from theaxial perspective, and a rotational or translational control medium toselect and/or view electrodes at different angular positions around acircumference of the lead from the cross-sectional perspective

The user interface also may present, on a selective basis, an electrodeview or a field view of the lead or leads. The electrode view or fieldview may present one or multiple perspectives such as axial andcross-sectional perspectives of a lead. In the electrode view, the userselects individual electrodes to form an electrode combination, andspecifies parameters for stimulation delivered via the electrodecombination. In a field view, the user manipulates a representation ofan electrical stimulation field produced by a selected electrodecombination. For example, the user may change the size, shape orposition of the field using graphical input media such as cursor orstylus control.

In the field view, the user may perform various field manipulationoperations such as a grow/shrink operation to expand or contract thesize of a field, a spread/focus operation to expand or contract thenumber of electrodes included in an electrode combination, and asplit/merge operation to divide a single electrode combination intomultiple combinations or vice versa. In response to such operations, aprogrammer selects appropriate electrode combinations, polarities,amplitudes, pulse widths, and pulse rates sufficient to support thespecified operation.

In some embodiments, the electrode view may permit a user to selectindividual electrodes from either an axial or cross-sectionalperspective. The user may use a combination of axial and rotational ortranslational input media to select individual electrodes or electrodecombinations, move an electrode combination up or down along the axiallength of the lead, or rotate or translate an electrode combinationaround the circumference of the lead. Likewise, the field view maypermit a user to manipulate fields from either an axial orcross-sectional perspective. For example, the user may expand a field bymanipulating an axial field representation or a cross-sectional fieldrepresentation.

In other embodiments, the programmer may automatically generatestimulation parameters that best fit a defined stimulation field createdby the user instead of manual electrode selection. One method ofgenerating the stimulation parameters may include creating a stimulationtemplate set from a plurality of stored volumetric stimulation templateswhich best fit a stimulation field that the user defined. The templateset is representative of stimulation parameters that will govern thestimulation therapy, and may be shown by the programmer in relation tothe stimulation field. The process of generating stimulation parametersfrom the stimulation field may be simplified through the selection of astimulation template, and the user may benefit by being shown the besttherapy that can be delivered from the defined stimulation field.

Further, in some embodiments, the field view of the stimulationparameters may be specific to patient 12 instead of utilizing generictissue characteristics. The programmer may generate an electrical fieldmodel according to the stimulation parameters, e.g., determined based ona user-defined stimulation field, and patient anatomy data stored in theprogrammer. The patient anatomy data may indicate one or morecharacteristics of patient tissue proximate to an implanted lead createdfrom any type of imaging modality, e.g., computed tomography, magneticresonance imaging, etc. The resulting electrical field may be presentedby the programmer in relation to one or more views of the lead. Theelectrical field illustrates to the user what the electrical propagationthrough the tissue would look like in contrast to the user-definedstimulation field. In addition, the programmer may apply a neuron modelthat indicates one or more characteristics of patient neural tissueproximate to an implanted lead to the electrical field model to generatean activation field model of the stimulation therapy defined by thestimulation field. The activation field model illustrates the actualneurons that will be activated by the electrical field. Similar to theelectrical field model, the activation field model may be presented tothe user by the programmer over the appropriate location of thedisplayed lead. The user may also modify the stimulation field basedupon the activation field model or simply alter the activation fieldmodel to create the desired therapy.

The techniques described herein may be used during a test or evaluationmode to select different electrode segment combinations in an effort toidentify efficacious electrode combinations. Additionally, thetechniques may be used to select different electrode combinationsassociated with different stimulation programs during an operationalmode, either directly or by selection of programs including suchelectrode combinations. For example, the techniques and associated userinterfaces may be implemented in a physician programmer used by aphysician to program a stimulator, in a patient programmer used by apatient to program or control a stimulator, or in an external stimulatorincluding both pulse generation and programming functionality. As afurther alternative, the programming techniques described herein are notnecessarily limited to use with implantable stimulators, and may be usedin conjunction with external stimulators that deliver stimulation, e.g.,via percutaneous leads.

FIG. 1 is a conceptual diagram illustrating an example stimulationsystem with a stimulation lead implanted in the brain of a patient. Asshown in FIG. 1, stimulation system 10 includes implantable stimulator20, lead plug 22, lead wire 24 and lead 14 implanted within patient 12.Specifically, lead 14 enters through cranium 16, e.g., via a burr holecap, and is implanted within brain 18 to deliver deep brain stimulation(DBS). One or more electrodes of lead 14 provide electrical pulses tosurrounding anatomical regions of brain 18 in a therapy that mayalleviate a condition of patient 12. In some embodiments, more than onelead 14 may be implanted within brain 18 of patient 12 to stimulatemultiple anatomical regions of the brain. An external programmer 19 maybe provided in the form of a handheld device, portable computer, orworkstation that provides a user interface to a physician or patient.The physician or patient interacts with the user interface to programstimulation parameters for implantable stimulator 20, or aneurostimulator, via external programmer 19.

Although application of implantable stimulator 20 to DBS is depicted inFIG. 1, implantable electrical stimulators incorporating one or moreleads with complex electrode array geometries may be used to deliverelectrical stimulation therapy to patients to treat a variety ofsymptoms or conditions such as chronic pain, tremor, Parkinson'sdisease, epilepsy, urinary or fecal incontinence, sexual dysfunction,obesity, or gastroparesis. For example, stimulation may be delivered viacomplex electrode array geometries to serve different therapeuticapplications, such as deep brain stimulation (DBS), spinal cordstimulation (SCS), pelvic stimulation, gastric stimulation, orperipheral nerve stimulation. Stimulation via complex electrode arraygeometries also may be used for muscle stimulation, e.g., functionalelectrical stimulation (FES) to promote muscle movement or preventatrophy. In addition, stimulation may be delivered via one, two or moreleads. DBS via one or two leads will be described for purposes ofillustration throughout this disclosure, but should not be consideredlimiting of the inventions as broadly embodied and described herein.

DBS may be used to treat dysfunctional neuronal activity in the brainwhich manifests as diseases or disorders such as Huntington's Disease,Parkinson's Disease, or movement disorders, for example. The exactmechanisms explaining why electrical stimulation therapy is capable oftreating such conditions of the brain are not fully known, but symptomsof these diseases can be lessened or eliminated with stimulationtherapy. Certain anatomical regions of brain 18 are responsible forproducing the symptoms of brain disorders. For example, stimulating ananatomical region called the Substantia Nigra in brain 18 may reduce thenumber and magnitude of tremors experienced by patient 12. Otherexamples include stimulation of the subthalamic nucleus, globus pallidusinterna, ventral intermediate nucleus, or zona inserta. Anatomicalregions such as these are targeted by the physician during implantationor lead 14 and programming of implantable stimulator 20. Duringimplantation, the physician attempts to position the lead as close tothese regions as possible.

Although DBS may successfully reduce symptoms of some neurologicaldiseases, the stimulation commonly causes unwanted side effects as well.Side effects may include incontinence, tingling, loss of balance,paralysis, slurred speech, loss of memory, and many other neurologicalproblems. Side effects may be mild to severe; however, most side effectsare reversible when stimulation is stopped. DBS may cause one or moreside effects by inadvertently providing electrical stimulation pulses toanatomical regions near the targeted anatomical region. For this reason,the physician typically programs the stimulation parameters in order tobalance effective therapy and minimal side effects to promote overalltherapeutic efficacy.

Typical DBS leads include one or more ring electrodes placed along thelongitudinal axis of the lead, such as lead 14. Each ring electrodeextends around the entire circumference of the lead. Therefore,electrical current from the ring electrodes propagates radially in alldirections from the active electrode. The resulting stimulation fieldreaches anatomical regions of brain 18 within a certain distance in alldirections. The stimulation field may reach the target anatomicalregion, but the stimulation field may also affect non-target anatomicalregions and produce unwanted side effects. Implanting a lead with a morecomplex electrode array geometry may help to customize the stimulationfield and provide improved therapy while decreasing side effects. Forexample, stimulation fields may be delivered on a more directional basisto more selectively target specific anatomical structures. By selectingelectrodes at particular angular positions, a field may be generallylimited to one side of a lead rather than all sides of the lead, makingthe field more directional.

Lead 14 has a complex electrode array geometry. In the example of FIG.1, lead 14 includes four electrode “levels” at different axial positionsalong the length of the lead. Each level includes four electrodesgenerally arranged in a ring. However, the electrodes are non-contiguouswith one another. The electrodes may be referred to as segmentedelectrodes or electrode segments. Each electrode is coupled to arespective electrical conductor within lead 14. Hence, lead 14 includesmultiple electrical conductors, e.g., wires, cables or the like, thatextend from the proximal end of the lead to respective electrodes toelectrically couple the electrodes to electrical terminals associatedwith implantable stimulator 20.

Each electrode is positioned at a different angular position around thecircumference of implantable lead 14, which has a generally circularcross-section in the example of FIG. 1. Each electrode is independentlyselectable so that stimulation energy can be delivered from the lead atdifferent axial and angular positions. In some embodiments, lead 14 mayinclude combinations of complex electrode array geometries and simpleelectrode array geometries. For example, ring electrodes that extendabout the entire circumference of the lead may be used in combinationwith electrodes disposed at different axial and angular positions.Selective activation of the electrodes carried by lead 14 can producecustomizable stimulation fields that may be directed to a particularside of lead 14 in order to isolate the stimulation field around atarget anatomical region of brain 18.

Producing directional or irregular stimulation fields with lead 14 notonly allows system 10 to more effectively treat certain anatomicalregions of brain 18, but can also reduce or eliminate side effectsrelative to spherical stimulation fields produced by a leads with simpleelectrode array geometries. The center of the stimulation field may bemoved away from lead 14 to avoid unwanted stimulation or compensate forinaccurately placed leads. Since leads may also migrate within brain 18or other stimulation sites slightly, a customizable stimulation fieldmay provide a longer duration of effective therapy as stimulation needsof patient 12 change.

Programming delivery of stimulation via lead 14 is more involved andcomplex when compared to leads having simple electrode array geometriesbecause of the increased number of electrode combinations and positions,and resulting stimulation fields. Effective programming may be difficultfor the physician if the physician is required to systematically selecteach electrode of lead 14 in order to find the electrode combinationsthat provide therapy and minimal side effects. While the physician maystill desire the ability to manually select certain general areas ofelectrodes of lead 14, i.e. the group of electrodes at one level of thelead, programming time may be reduced if the physician is able to viewthe lead from different positions and manipulate axial and rotational ortranslational controls in an electrode view or field view. In addition,the physician may be able to manipulate or even initially define astimulation field in a field view such that the programmer automaticallygenerates the stimulation parameters that would produce the stimulationfield in patient 12, in contrast to manually selecting electrodecombinations and stimulation parameters. These aspects of programmingthe stimulation parameters will be further discussed in more detail.

The user interface of programmer 19 displays, e.g., with a liquidcrystal display (LCD), a representation of lead 14 with multipleperspectives, e.g., an axial perspective and a cross-sectionalperspective. The multiple perspectives may be displayed individually ona selective basis, or simultaneously so that the user can view two ormore perspectives at the same time. In effect, axial and cross-sectionalperspectives provide two different two-dimensional perspectives thattogether illustrates a three-dimensional electrode programming space.

In some embodiments, lead 14 may be represented on the display of theuser interface in conjunction with a representation of a targetanatomical region, such as the brain or spinal cord, and positionedaccording to the actual implantation location. The positioning of therepresentation of the lead 14 relative to the anatomical region can becontrolled manually by the physician or directly from imaginginformation taken indicating the actual position of the lead withinbrain 18.

The physician interacts with the user interface to manually select andprogram particular electrodes of lead 14 via an electrode selectionview, or select an electrode level of the lead and adjust the resultingstimulation field. Once the physician has defined the one or morestimulation fields, programmer 19 generates the stimulation parametersassociated with each of the stimulation fields and transmits theparameters to implantable stimulator 20. Hence, the user interface ofprogrammer 19 may permit the user to manually select electrodecombinations and associated stimulation parameters, or simply specifyand manipulate a stimulation field in terms of size, direction andshape, in which case programmer 19 or implantable stimulator 20automatically adjusts electrode combinations and parameters toapproximate the desired stimulation field. In some embodiments, the userinterface may restrict the ability of the physician to define thestimulation fields based upon the stimulation capabilities ofimplantable stimulator 20 and lead 14. For example, the physician maynot make the stimulation field larger when the voltage or currentamplitude cannot be increased any further, or when no more electrodesare available in the desired direction of the stimulation field.

Additionally, the user interface may restrict the physician fromapplying the stimulation field to anatomical regions specifically bannedfrom stimulation. These anatomical regions may severely alter thephysiology of patient 12 and cause detrimental side effects orirreversible side effects. Accordingly, the physician may manuallylockout potentially unsafe electrodes or electrode levels based upon theactual implantation location of the lead. Therefore, the user interfacemay be configured to prevent the physician from selecting particularelectrodes during the programming of stimulation parameters.Alternatively, or additionally, some electrodes or electrode levels mayhave predetermined parameter ranges that cannot be violated. Forexample, a minimum field value or parameter value may be specified tomaintain field strength at a minimum level. Similarly, a maximum fieldvalue or parameter value may be specified to prevent stimulation inexcess of a given level.

In some embodiments where the physician may define the stimulation fieldor modify a stimulation field from the electrode view, programmer 19generates the stimulation parameter values required by the stimulationfield and transmits the parameter values to implantable stimulator 20via wireless telemetry. The parameter values may also be saved onprogrammer 19 for review at a later time. In some cases, programmer 19may not be capable of generating stimulation parameter values that canproduce the defined stimulation field within brain 18. Programmer 19 maydisplay an error message to the physician alerting the physician toadjust the stimulation field. Programmer 19 may also display a reasonwhy the stimulation field cannot be provided, such as the field is toolarge or an electrode is malfunctioning and cannot be used. Other errorsmay also be displayed to the physician. In addition, programmer 19 mayprompt the physician to return to the electrode view to manually selectstimulation parameters if a stimulation field is unacceptable.

The user interface may or may not be used to provide real-timeprogramming of implantable stimulator 20. In one case, the physicianuses the user interface to define stimulation fields, and programmer 19generates the stimulation parameters when the physician has determinedthat the stimulation field is ready for therapy. In this manner,stimulation therapy perceived by patient 12 does not change at the sametime the physician changes the stimulation field. In another case,however, the user interface could be used in a real-time programmingenvironment to immediately adjust stimulation in response to changesmade by the physician using the field view or electrode view.

System 10 may also include multiple leads 14 or electrodes on leads ofother shapes and sizes. The user interface may allow the physician toprogram each lead simultaneously or require the physician to programeach lead separately. In some DBS patients, two leads 14 are implantedat symmetrical locations within brain 18. For example, a first lead maybe placed in the right hemisphere of brain 18 and a second lead may beplaced at the same location within the left hemisphere of the brain.Programmer 19 may allow the physician to create a stimulation field forthe first lead and create a mirrored stimulation field for the secondlead. The physician may be able to make fine adjustment to eitherstimulation field to accommodate the slight anatomical regiondifferences between the left and right hemispheres.

While lead 14 is described for use in DBS applications throughout thisdisclosure as an example, lead 14, or other leads, may be implanted atany other location within patient 12. For example, lead 14 may beimplanted near the spinal cord, pudendal nerve, sacral nerve, or anyother nervous or muscle tissue that may be stimulated. The userinterface described herein may be used to program the stimulationparameters of any type of stimulation therapy. In the case of pelvicnerves, defining a stimulation field may allow the physician tostimulate multiple desired nerves without placing multiple leads deepinto patient 12 and adjacent to sensitive nerve tissue. Therapy may alsobe changed if leads migrate to new locations within the tissue orpatient 12 no longer perceives therapeutic effects of the stimulation.

FIGS. 2A and 2B are conceptual diagrams illustrating two differentimplantable stimulation leads. Leads 26 and 34 are embodiments of lead14 shown in FIG. 1. As shown in FIG. 2A, lead 26 includes four electrodelevels 32 (includes levels 32A-32D) located at various axial positionsalong the lengths of lead housing 30. In a DBS application, a retentiondevice may reside on or within a burr hole in cranium 16 to secure theposition of lead 26 within brain 18.

Lead 26 is implanted within brain 18 at a location determined by thephysician to be near an anatomical region to be stimulated. Electrodelevels 32A, 32B, 32C, and 32D are equally spaced along the length oflead housing 30. Each electrode level 32 may have two or more electrodeslocated at different angular positions around the circumference of leadhousing 30. In one embodiment, each electrode level 32 includes fourseparate electrodes at four different angular positions. Electrodes atdifferent levels, but the same angular positions, may be aligned withone another in a direction parallel to the longitudinal axis of lead 26.

Alternatively, electrodes of different electrode levels may be staggeredat different angular positions around the circumference of lead housing30. Also, in some embodiments, different electrode levels may includedifferent numbers of electrodes. For example, one electrode level at oneaxial position may include a single ring electrode that extends aroundthe entire circumference of lead 26, while another electrode level atanother axial position may include two electrodes at different angularpositions, another electrode level at another axial position may includethree electrodes at different angular positions, and another electrodelevel at another axial position may include four electrodes at differentangular positions. In addition, lead 26 or 34 may include asymmetricalelectrode locations around the circumference of each lead or electrodesof the same level that have different sizes. These electrodes mayinclude semi-circular electrodes that may or may not becircumferentially aligned between electrode levels. Various combinationsof electrode levels having different numbers of electrodes arecontemplated.

In some embodiments, lead housing 30 may include a radiopaque stripe(not shown) along the outside of the lead housing. The radiopaque stripecorresponds to a circumferential location that allows the physician toidentify electrodes in a transverse cross-sectional view of lead 26 withrespect to the orientation of the lead within tissue of patient 12.Using the images of patient 12, the physician can use the radiopaquestripe as a marker to assess the exact orientation of lead 26 within thebrain of patient 12. Orientation of lead 26 may be needed to easilyprogram the stimulation parameters without providing the actual anatomyof patient 12 to the physician with respect to lead 26. In otherembodiments, a marking mechanism other than a radiopaque stripe may beused to identify the orientation of lead 14. These marking mechanismsmay include something similar to a tab, detent, or other structure onthe outside of lead housing 30. In some embodiments, the physician maynote the position of markings along lead wire 24 during implantation todetermine the orientation of lead 14 within patient 12.

FIG. 2B illustrates a lead 34 that includes more electrode levels thanlead 26. Lead 34 includes mounting base 36 and lead housing 38. In theexample of FIG. 2B, eight electrode levels 40 (40A-40H) are located atthe distal end of lead 34. Each electrode level 40 is evenly spaced fromthe adjacent electrode level and includes one or more electrodes. In apreferred embodiment, each electrode level 40 includes fourcircumferential electrodes. Therefore, lead 34 includes 32circumferential electrodes in the example of FIG. 2B. Each electrode maybe substantially rectangular in shape. Alternatively, the individualelectrodes may have alternative shapes, e.g., circular, oval,triangular, or the like.

In alternative embodiments, electrode levels 32 or 40 are not evenlyspaced along the longitudinal axis of the respective leads 26 and 34.For example, electrode levels 32C and 32D may be spaced approximately 3millimeters (mm) apart while electrodes 32A and 32B are 10 mm apart.Variable spaced electrode levels may be useful in reaching targetanatomical regions deep within brain 18 while avoiding potentiallydangerous anatomical regions.

Leads 26 and 34 may be substantially rigid to prevent the implanted leadfrom varying from the expected lead shape. Leads 26 or 34 may besubstantially cylindrical in shape. The leads may be substantiallystraight and rigid, or include one or more curves to reach targetanatomical regions of brain 18. In some embodiments, leads 26 or 34 maybe similar to a flat paddle lead or a conformable lead shaped forpatient 12. Also, in other embodiments, leads 26 and 34 may any of avariety of different polygonal cross sections taken transverse to thelongitudinal axis of the lead.

Lead housings 30 and 38 may continue directly into lead wire 24. Leadhousing 30 or 38 may include a right angle connector that allows lead 26and 34 to be inserted into cranium 16. Alternatively, the entire leadextending from the stimulator (or a lead extension) to the stimulationsite may have a continuous lead body. For example, the lead may beuniform as it leaves the burr hole in the head. A retention devicesqueezes the lead as it leaves the burr hole and the lead is thensmoothly bent over at approximately 90 degrees to continue onto theoutside of the skull and under the skin. The lead may continue to aproximal connector end which will have full ring or half ring connectorelectrodes. The connector end plugs into an extension. The extensioncontinues down to the stimulator. In embodiments of system 10 includingtwo or more leads 14, each lead may be connected to only one lead wire24. In this case, a connector at the surface of cranium 16 may coupleeach lead 14 to lead wire 24.

FIGS. 3A-3D are transverse cross-sections of example stimulation leadshaving one or more electrodes around the circumference of the lead. Asshown in FIGS. 3A-3D, one electrode level, such as one of electrodelevels 32 and 40 of leads 26 and 34, respectively, are shown to includeone or more electrodes. FIG. 3A shows an electrode level 42 thatincludes circumferential electrode 44. Circumferential electrode 44encircles the entire electrode level 42 and forms a conventional ringelectrode. Circumferential electrode 44 may be utilized as a cathode oranode as configured by the user interface.

FIG. 3B shows electrode level 46 which includes two electrodes 48 and50. Each electrode 48 and 50 wraps approximately 170 degrees around thecircumference of electrode level 46. Spaces of approximately 10 degreesare located between electrodes 48 and 50 to prevent inadvertent couplingof electrical current between the electrodes. Each electrode 48 and 50may be programmed to act as an anode or cathode.

FIG. 3C shows electrode level 52 which includes three equally sizedelectrodes 54, 56 and 58. Each electrode 54, 56 and 58 encompassesapproximately 110 degrees of the circumference of electrode level 52.Similar to electrode level 46, spaces of approximately 10 degreesseparate electrode 54, 56 and 58. Electrodes 54, 56 and 58 may beindependently programmed as an anode or cathode for stimulation.

FIG. 3D shows electrode level 60 which includes four electrodes 62, 64,66 and 68. Each electrode 62-68 covers approximately 80 degrees of thecircumference with approximately 10 degrees of insulation space betweenthe electrodes. In other embodiments, up to ten or more electrodes maybe included within an electrode level. In alternative embodiments,consecutive electrode levels of lead 14 may include a variety ofelectrode levels 42, 46, 52 or 60. For example, lead 14 may includealternative electrode levels of electrode levels 62 and 60 depicted inFIGS. 3C and 3D. In this manner, various stimulation field shapes may beproduced within brain 18 of patient 12. In addition, circumferentialelectrodes may not be aligned along the length of their respective lead.Further, the above-described sizes of electrodes within an electrodelevel are merely examples, and the invention is not limited to theexample electrode sizes.

Also, the insulation space, or non-electrode surface area, betweenadjacent electrodes may be of varying size. Generally, the space may bebetween approximately 1 degree and approximately 20 degrees. Morespecifically, the space may be between approximately 5 and approximately15 degrees. Smaller spaces may allow a greater volume of tissue to bestimulated. In alternative embodiments, circumferential electrode sizemay be varied around the circumference of an electrode level. Inaddition, insulation spaces may vary in size as well. Such unsymmetricalelectrode levels may be used in leads implanted at tissues needingcertain shaped stimulation fields.

FIG. 4 is a block diagram illustrating an example implantable stimulator20 for delivery of electrical stimulation therapy via one or more leadshaving a complex electrode array geometry. As shown in FIG. 4, theimplantable stimulator 20 includes lead 14 (of FIG. 1), processor 70,memory 72, stimulation generator 80, switch device 82, power supply 86,and telemetry interface 84. Stimulator 20 delivers neurostimulationtherapy via electrodes carried by one or more leads 14. Again, theelectrodes may be arranged in a complex electrode array geometry. In theexample illustrated in FIG. 4, lead 14 includes four electrode levels,each of which may include multiple non-contiguous electrodes atdifferent angular positions about the circumference of the lead. Theconfiguration, type, and number of electrodes illustrated in FIG. 4 aremerely exemplary. For example, implantable stimulator 20 may include anynumber of leads 14 that each has any number of electrodes.

Memory 72 includes computer-readable instructions that, when executed byprocessor 70, cause stimulator 20 to perform various functions. Memory72 may include any volatile, non-volatile, magnetic, optical, orelectrical media, such as a random access memory (RAM), read-only memory(ROM), non-volatile RAM (NVRAM), electrically-erasable programmable ROM(EEPROM), flash memory, or any other digital media. Memory 72 mayinclude programs 74, program groups 76, and operating instructions 78 inseparate memories within memory 72 or separate areas within the memory.Each program 74 defines a particular program of therapy in terms ofelectrode combination, electrode polarity, current or voltage amplitude,pulse width and pulse rate. A program group 76 defines a group ofprograms that may be delivered together on an overlapping ornon-overlapping basis. Operating instructions 78 guide general operationof the neurostimulator under control of processor 70.

Stimulation generator 80 produces stimulation pulses for delivery to thepatient via selected electrode combinations. In other embodiments,stimulation generator 80 may produce continuous sine waves or othernon-pulse signals for delivery to patient 12. Processor 70 controlsstimulation generator 80 according to programs 74 and program groups 76stored in memory 72 to apply particular stimulation parameters specifiedby one or more of programs, such as amplitude, pulse width, and pulserate. Processor 70 may include a microprocessor, a controller, a digitalsignal processor (DSP), an application specific integrated circuit(ASIC), a field-programmable gate array (FPGA), or equivalent discreteor integrated logic circuitry.

Processor 70 also controls switch device 82 to apply the pulsesgenerated by stimulation generator 80 to selected electrode combinationscarried by lead 14. In particular, switch device 82 couples stimulationpulses to selected conductors within lead 14 which, in turn, deliver thestimulation pulses across selected electrodes. Switch device 82 may be aswitch array, switch matrix, multiplexer, or any other type of switchingdevice suitable to selectively couple stimulation energy to selectedelectrodes. Hence, stimulation generator 80 is coupled to electrodes viaswitch device 82 and conductors within lead 14.

Stimulation generator 80 may be a single- or multi-channel stimulationgenerator. In particular, stimulation generator 80 may be capable ofdelivering, a single stimulation pulse, multiple stimulation pulses, orcontinuous signal at a given time via a single electrode combination ormultiple stimulation pulses at a given time via multiple electrodecombinations. In some embodiments, however, stimulation generator 80 andswitch device 82 may be configured to deliver multiple channels on atime-interleaved basis. In this case, switch device 82 serves to timedivision multiplex the output of stimulation generator 80 acrossdifferent electrode combinations at different times to deliver multipleprograms or channels of stimulation energy to patient 12.

For testing of electrode combinations, processor 70 controls stimulationgenerator 80 to smoothly shift stimulation energy between differentelectrode combinations. In response, stimulation generator 80 shiftsbetween electrode combinations of different programs by incrementallyadjusting the amplitudes of the electrode combinations to smoothly shiftfrom one electrode combination to another. For example, processor 70 maybe responsive to changes in the programs, as received from programmer19, to control switch device 82 and stimulation generator 80 to deliverstimulation pulses or groups of pulses to different electrodecombinations.

The external programmer 19 controls stimulator 20 to test electrodecombinations so that a user may identify desirable combinations.Telemetry interface 84 supports wireless communication betweenimplantable stimulator 20 and an external programmer 19 under control ofprocessor 70. Telemetry interface 84 may allow processor 70 tocommunicate with programmer 19 during the electrode testing process. Inparticular, processor 70 receives, as updates to programs, values forstimulation parameters such as amplitude and electrode combination, fromprogrammer 19 via telemetry interface 84, and delivers one or morestimulation pulses according to the received stimulation parameters.

The various components of implantable stimulator 20 are coupled to powersupply 86, which may include a rechargeable or non-rechargeable battery.A non-rechargeable battery may be selected to last for several years,while a rechargeable battery may be inductively charged from an externaldevice, e.g., on a daily or weekly basis. In other embodiments, powersupply 86 may be powered by proximal inductive interaction with anexternal power supply carried by patient 12.

FIG. 5 is a block diagram illustrating an example programmer forprogramming and controlling the implantable stimulator of FIG. 4. In theexample of FIG. 5, programmer 19 includes processor 88, memory 90,telemetry interface 108, power supply 110 and user interface 98. Ingeneral, a user, i.e., a physician or patient, uses programmer 19 toprogram and control implantable stimulator 20 shown in FIG. 4.

In the example of FIG. 5, memory 90 stores programs 94 specifyingelectrode combinations, electrode polarities, and stimulation parametersfor download to the implantable stimulator 20. Memory 90 may include anyvolatile, non-volatile, magnetic, optical, or electrical media, such asa random access memory (RAM), read-only memory (ROM), non-volatile RAM(NVRAM), electrically-erasable programmable ROM (EEPROM), flash memory,or any other digital media.

In addition to programs 94, memory 90 may store an evaluation sequence92 that guides the user in selection of electrode combinations andstimulation parameters, or automatically selects electrode combinationsand stimulation parameters for evaluation of efficacy. For example,evaluation sequence 92 may specify a predetermined progression ofelectrode combinations to be selected for evaluation, or provide rulesfor dynamic selection of electrode combinations during the course ofevaluation.

Memory 90 also may record efficacy information 96 for particularprograms 94. Specifically, upon selection of an electrode combinationand stimulation parameters as a program, programmer 19 may directimplantable stimulator 20 to apply the program. Upon application of theprogram, the patient may provide feedback concerning efficacy. The user,which may be a physician or the patient, then records the efficacyinformation in memory 90 of programmer 19. In this manner, differentprograms can be rated in terms of efficacy so that the user ultimatelymay select an effective electrode combination and stimulationparameters.

A user interacts with processor 88 via user interface 98 in order toidentify efficacious electrode combinations and stimulation parametersas described herein. Processor 88 may provide display 100, i.e., agraphical user interface (GUI), via user interface 98 to facilitateinteraction with the user. Processor 88 may include a microprocessor, amicrocontroller, a DSP, an ASIC, an FPGA, or other equivalent discreteor integrated logic circuitry. The user interface may include display100 and one or more input media. In addition, the user interface mayinclude lights, audible alerts, or tactile alerts.

Notably, as shown in FIG. 5, the input media of user interface 98includes rotational controller 102 and axial controller 104. Axialcontroller 104 permits a user to move electrode combinations orstimulation fields up or down along the length of a lead, i.e., lead 14,by selecting different combinations of electrodes. Rotational controller102 permits the user to move electrode combinations or stimulationfields around the lead by selecting combinations of electrodes atdifferent angular positions. In addition, axial controller 104 androtational controller 102 may be configured to permit the user to viewdifferent electrodes, e.g., from multiple perspectives. User interface98 also may present selection media 106 to permit the user to selectparticular electrode combinations for activation.

Using evaluation sequence 92, processor 88 may run a user-controlledtest of a predetermined or dynamically generated sequence of electrodecombinations to identify effective electrode combinations foralleviating symptom areas. Processor 88 may receive a pre-defined set ofelectrode combinations to test from a physician and store thepre-defined set of electrode combinations as a set of programs, eitheralone or in combination with stimulation parameters. Alternatively,processor 88 may execute an electrode combination search algorithmaccording to evaluation sequence stored 92 in memory 90 to selectindividual electrodes or electrode combinations to test.

Processor 88 controls stimulator 19 via telemetry interface 108 to testselected electrode combinations by controlling the stimulator to deliverneurostimulation therapy to patient 12 via the selected electrodecombinations. In particular, processor 88 transmits programming signalsto implantable stimulator 20 via telemetry interface 108. As a sequenceof electrode combinations proceeds, the programming signals may betransmitted at a rate consistent with the control input provided by auser. In this manner, the user may quickly observe the effects of eachincrement in the change between electrode combinations. In some cases,e.g., for DBS applications, effects of an electrode or parameter changemay not be immediately evident. In such cases, a change may be activatedand evaluated over a period of minutes, hours, or days before anotherchange is initiated.

After completion of electrode testing, processor 88 may transmit one ormore of the programs created by the physician to stimulator 20 viatelemetry interface 108 for storage in the stimulator, or to anotherprogrammer used by patient 12 to control delivery of neurostimulationtherapy, e.g., via wireless or wired input/output interface. In eithercase, the selected electrode combinations can then be used to delivertherapy chronically or over an extended period of time.

Programmer 19 may be provided in the form of a handheld device, portablecomputer, or workstation that provides a user interface to a physicianor patient. The physician or patient interacts with user interface 98 toprogram stimulation parameters for implantable stimulator 20 viaexternal programmer 19. Hence, various aspects of user interface 98described herein may be provided in the form of physician programmer, apatient programmer or both.

FIGS. 6-21 are schematic diagrams illustrating example user interfacespresented by embodiments of programmer 19 of FIG. 5. In each example,the user interface is an embodiment of user interface 98 of FIG. 5, andmay provide axial and rotational or translational input media to moveelectrode combinations axially or rotationally, view leads fromdifferent perspectives, e.g., side or cross-sectional, and move electricstimulation fields axially or rotationally. In addition, in someembodiments, the user interface may provide field views and electrodeviews.

In the electrode view, the user selects individual electrodes to form anelectrode combination, and specifies parameters for stimulationdelivered via the electrode combination. In a field view, the usermanipulates a representation of an electrical stimulation field producedby a selected electrode combination. For example, the user may changethe size, shape or position of the field using graphical input mediasuch as cursor or stylus control. In some embodiments, the user may beable to create a stimulation field in the field view and direct theprogrammer to generate stimulation parameters that would best match thestimulation field.

In the field view, the user may perform various field manipulationoperations such as a grow/shrink operation to expand or contract thesize of a field, a spread/focus operation to expand or contract thenumber of electrodes included in an electrode combination, and asplit/merge operation to divide a single electrode combination intomultiple combinations or vice versa. In response to such operations, aprogrammer selects appropriate electrode combinations, polarities,amplitudes, pulse widths, and pulse rates sufficient to support thespecified operation.

In the example of FIG. 6, a user interface 112 is provided by aprogrammer 114. User interface 112 includes a display screen 115 thatshows a single lead having four electrode levels. Display screen 115 maybe a touchscreen such that interactive media may be placed on thescreen. Alternatively, or in addition, keys, buttons, wheels and otherinput devices may be provided on programmer 114, independently ofdisplay 115. Each electrode level includes four electrodes arranged atdifferent angular positions around the circumference of the lead. Userinterface 112 provides a side view 116 of the lead, and across-sectional view 120 of the lead, e.g., the representation of lead14. Side view 116 shows all of the electrodes along one side of thelead. In particular, side view 116 is a two-dimensional view thatillustrates approximately 180 degrees of the circumference of the lead,and the axial length of a distal portion of the lead. In systems thatinclude more than one lead 14 implanted within patient 12, userinterface 112 may provide lead representations of two or more of theleads instead of just a single side and cross-sectional view of onelead.

With a complex electrode array geometry, however, side view 116 does notpermit the user to view all electrodes carried by the lead. Again, theview is limited to only one side of the lead. To provide a more completeview, user interface 112 presents another perspective. In particular,cross-sectional view 120 shows a top view, or axial view, of one levelof electrodes on the lead. In the example of FIG. 6, the third level ofelectrodes is shown in side view 116 and includes a cathode (+) andanode (−) in the visible electrodes. Again, however, it is not possibleto view the other side of the lead in side view 116. For this reason,cross-sectional view 120 is provided to present electrodes on all sidesof the lead at the electrode level being considered.

In the example of FIG. 6, cross-sectional view 120 reveals that there isanother cathode in the third electrode level on the side of the leadthat is not visible in the side view. The cross-sectional view 120 mayinclude a horizontal dashed line that divides the bottom (front) and top(back) sides of the lead to indicate which portion is visible in theside view 116. In other words, the bottom half of the lead in thecross-sectional view corresponds to the visible (front) side of the leadin the side view 116. The top half of the lead in the cross-sectionalview corresponds to the back side of the lead, which is not visible inthe side view 116.

Cross-sectional view 120 also may include an arrow 122 that provides anorientation to cross-sectional view 120. For example, arrow 122 may becoincident with a radio-opaque stripe or marker carried by the lead.Alternatively, arrow 122 may indicate a point of reference relative toan anatomical structure near the implanted lead 14. In the context ofDBS, for example, arrow 122 may point to the front, back or a selectedside of a patient's cranium when viewed as a horizontal plane from thetop.

Arrow 122 may be positioned based on known positioning data for lead 14upon implantation within brain 18. The presentation of arrow 122 helpsmaintain the physician's or patient's orientation as the lead is rotatedas described herein. As the user views the other side of the lead in theside view, for example, it may be difficult to immediately comprehendthe spatial relationship between the electrodes on that side and thetarget anatomy. Simultaneous display of side view 116 andcross-sectional view 120 with arrow 120 may help to maintain the user'sorientation.

As further shown in FIG. 6, user interface 112 may further includeup/down arrows 124 and side-to-side arrows 126 or other equivalent inputmedia such as vertical and horizontal scroll bars, scroll wheels, arrowbuttons, or the like. Up/down arrows 124 serve as an axial control topermit the user to move electrode combinations up or down the length ofthe lead in the side view 116. For example, a user may walk a bipole upand down the lead to test different electrode positions. Side-to-sidearrows 126 serve as a rotational control to permit the user to rotatethe lead so that side view 116 rotates to reveal other electrodes ondifferent sides of the lead. At the same, time, the side-to-side arrows126 are used to rotate the cross-sectional view 120 so that thecross-sectional view always corresponds to an electrode level currentlyvisible within the side view 116.

Side-to-side arrows 126 also rotate side view 116 to provide the userwith access to another side of the lead to select additional oralternative electrodes. In the example of FIG. 6, only a singlecross-sectional view 120 is presented by user interface 112 at a giventime. For example, the cross-sectional view 120 may correspond to anelectrode level that is presently being manipulated by the user. In FIG.6, electrode level 3 (counting from the top of the lead to the bottom ofthe lead) is highlighted in a dashed box. The dashed box may indicatethat the user has selected electrode level 3, e.g., with a stylus orother pointing media, or with up/down arrows 124, and that the user isadjusting the parameters for that combination of electrodes. An exampleof a stylus 118 is shown in FIG. 6.

In some embodiments, the user may select electrode combinations withstylus 118 by clicking on individual electrodes in the side view 116. Insome embodiments, the user also may select electrodes with stylus 118 byclicking on electrodes in the cross-sectional view. Hence, the user mayrely on side view 116 or cross-sectional view 120 to select individualelectrodes for inclusion in an electrode combination. To specify whetherthe electrode is to serve as an anode or cathode, the user may clickmultiple times on a given electrode. For example, the user may clickonce to select an electrode, twice to make the electrode an anode, threetimes to make the electrode a cathode, and four times to deselect theelectrode.

When the user actuates the up/down arrows 124 to access a differentelectrode level in the side view 116, the highlighted or dashed boxmoves to track the up/down input and identify another electrode level.At the same time, the cross-sectional view 120 changes to depictelectrodes at the newly selected electrode level. Hence, thecross-sectional view 120 illustrates the electrodes associated with oneelectrode level at a time, but changes to illustrate other levels as theuser moves up or down to access different levels within the side view116.

In other words, if the user has selected an electrode on electrode level3, cross-sectional view 120 shows all of the electrodes at the variousangular positions on level 3 and presents the portion of the lead thatis visible in side view 116 below the horizontal line. If the user thenselects an electrode on electrode level 1 in side view 116, thecross-sectional view 120 immediately tracks the change and shows all ofthe electrodes on electrode level 1. In addition, the user may proceedto select additional electrodes either within side view 116, e.g., tochange levels, or within cross-sectional view 120, e.g., to select ordeselect electrodes in that corresponding electrode level of the lead.

For each electrode combination selected by a user, the user may alsospecify stimulation parameters as shown in FIG. 6. For example, the usermay specify voltage or current amplitude, pulse width, and pulse ratefor stimulation pulses to be delivered via the selected electrodecombination shown in the side and cross-sectional views 116 and 120. Theuser may use up/down arrows to change the values for respectiveparameters or directly enter values if numeric input is available inprogrammer 114.

Upon selecting an electrode combination and desired parameters, the usermay download the combination and parameters to implantable stimulator 20as a program or as adjustments to an existing program, and thereby causethe stimulator to apply the program. For example, the user may press a“program” (apply) button, in which case programmer 114 downloadsinstructions sufficient for stimulator 20 to carry out the desiredprogram change. Downloads may be sent to stimulator 20 on a frequentbasis to test numerous electrode combinations and parameter values. Insome cases, the download may specify both an electrode combination andparameter values. In other cases, the download may be only an electrodecombination or only a parameter change.

In the illustrated example, the electrode combinations and parametervalues selected via programmer 114 may be downloaded at the instructionof a user, e.g., by pressing the “Apply” button shown in FIG. 6. Forexample, the user may specify an electrode combination and specifyparameter values, and then instruct programmer 114 to download theprogram or program adjustments. Alternatively, in some embodiments, orin a selectable mode of operation, programmer 114 may transmit thechanges to stimulator 20 substantially in real time so that a programpresently being applied by the stimulator is adjusted as the useradjusts the electrode combination or parameter values.

For example, when the user adds an additional electrode to an electrodecombination, removes an electrode from an electrode combination, changesthe polarity of an electrode, or adjusts a parameter value, programmer114 may immediately apply the selection, polarity change or adjustmentto stimulator 20 so that the stimulation delivered by the stimulatorimmediately tracks the user's program changes. In this manner,stimulation may be smoothly shifted between different electrodecombinations to identify combinations and parameter values that supporttherapeutic efficacy.

FIG. 7 is substantially identical to FIG. 6, but illustrates rotation ofthe lead in both the side view 128 and cross-sectional view 130. In theexample of FIG. 7, the user has used user interface 114 and pressed theleft side-to-side 124 to rotate the lead to left in side view 128 whencompared to FIG. 6. Cross-sectional view 130 tracks the side view andshows that the + and − electrodes have rotated clock-wise such that aportion of the + electrode is above the horizontal line, indicating thatit is not visible in side view 128. In addition, arrow 122 rotates withthe lead in cross-sectional view 130 to preserve the user's sense oforientation of the lead relative to an anatomical structure.

FIG. 8 is similar to FIGS. 6 and 7, but illustrates an exampleembodiment in which user interface 132 displays multiple cross-sectionalviews 140A, 140B, 140C, 140D are presented simultaneously so that theuser can view the electrodes in all electrode levels of the lead. Eachcross-sectional view 140A-140D (collectively “cross-sectional views140”) corresponds substantially to cross-sectional views 120 and 130 ofFIGS. 6 and 7. Cross-section views 140 are presented adjacent to thecorresponding electrode level in side view 138 of the lead. For example,cross-sectional views 140 correspond to electrode levels 1, 2, 3 and 4(from top to bottom) in side view 138 of the lead. As the lead isrotated in response to actuation of arrows 146, cross-sectional views140 track the rotation and may include the horizontal line and arrow 122shown in FIGS. 6 and 7, to aid in maintaining user orientation.

FIG. 9 illustrates an alternative embodiment of user interface 98.Instead of displaying multiple cross-sectional views 140 or a singlecross-sectional view 120, user interface 148 of FIG. 9 includes anested, coaxial, cross-sectional view, i.e., concentric axial view 156,of the various electrode levels of the lead. In particular, FIG. 9 showsside view 154 and arrows 160 and 162, but includes a concentric axialview 156 in which the electrodes arranged at different angular positionswithin the electrode levels or the lead are displayed concentrically. Inthis manner, all electrodes can be presented simultaneously in a morecompact format, which may be especially desirable for smaller, handheldprogrammer 150 or applications in which more controls are to bepresented to the user at once. In systems that include more than onelead 14 implanted within patient 12, user interface 148 may provide leadrepresentations of two or more of the leads instead of just a singleside and concentric axial view of one lead.

The electrodes for electrode level 1 (at the top of the lead) are shownin a first, innermost layer of concentric axial view 156. The electrodesfor electrode levels 2, 3 and 4 are then shown in the second, third andfourth layers of the concentric axial view, where the fourth layer is anoutermost layer. Again, the horizontal line and arrow 158 may bepresented to aid in maintaining orientation. The electrodes in theconcentric layers of concentric axial view 156 include + or − signs toindicate whether the electrodes have been selected and, if so, thepolarity of the electrode. In addition to viewing the electrodes inconcentric axial view 156, a user may select the electrodes in theconcentric axial view, e.g., with a stylus, by clicking on theelectrodes and then clicking repeatedly to specify polarity or deselectthe electrode as mentioned previously.

FIG. 10 illustrates another alternative embodiment of a user interface161 provided by a programmer 163. In the example of FIG. 10, theelectrodes at the various angular positions around the circumference ofthe lead are illustrated in user interface 161 as unwrappedtwo-dimensional (2D) array view 164 as if the cylindrical surface of thelead were “unrolled” and laid out flat. In this case, all electrodes andelectrode levels are simultaneously visible. Arrows 168 and 170 may beused to move electrode combinations up/down or side-to-side,respectively. In particular, arrows 170 permit the user to simulaterotation of an electrode combination around the circumference of thelead. In systems that include more than one lead 14 implanted withinpatient 12, user interface 161 may provide lead representations of twoor more of the leads instead of just an unwrapped view of one lead.

An orientation arrow 166 may be provided to show the orientation of thelead relative to an anatomical structure such as the front of thepatient's cranium. As in the previous examples, a user may selectindividual electrodes and polarities by clicking on the electrodes witha stylus. Once an electrode combination is select, the user may “walk”the combination up, down, or around the unwrapped 2D array view 164using arrows 74, 76. In addition, user interface 161 of FIG. 10 permitsthe user to adjust stimulation parameter values such as amplitude, pulsewidth and frequency.

In FIGS. 6-10, user interfaces 112, 132, 148 and 161 present anelectrode view in which a user selects individual electrodes,combinations of electrodes, and stimulation parameter values, and viewsthe electrodes using either an side view or a cross-sectional view withthe aid of rotational control media. In each example, each userinterface may further include a “Field View” button that enables theuser to selectively activate a different viewing mode. In the field viewmode, the user may or may not select individual electrodes, depending ondesign considerations. However, the field view permits the user tomanipulate a representation of a stimulation field produced by anelectrode combination and a set of parameter values.

FIG. 11 illustrates user interface 172 that presents field view 175 of alead having a complex electrode array geometry. FIG. 12 is similar toFIG. 11 but illustrates the presentation of multiple cross-sectionalviews of the lead in alignment with corresponding electrode levels ofthe lead in a field view 198. In the example of FIGS. 11 and 12, theuser has selected an initial electrode combination, either manually orby selection for a set of electrode combinations provided by programmer174, and has transitioned to field views 175 or 198 of the electrodecombination. In the field view, user interface 172 presents arepresentation of a stimulation field 178 defined by the user andproduced by the electrode combination, given the parameter valuesassociated with stimulation delivered by the electrode combination andgeneral tissue characteristics stored within programmer 174.

The size and shape of stimulation field 178 may be established based ongeneric physical characteristics of human tissue and known physicalcharacteristics of the electrodes of lead 14. In other words,stimulation field 178 displayed in field view 175 may only be anapproximation of what the stimulation field would be in brain 18.However, in some embodiments, physical characteristics of the actualanatomical structure of patient 12 being treated may be used to generatestimulation field 178. This anatomical structure information may bepresented to programmer 174 in the form of patient anatomical datagenerated by an imaging modality, such as computed tomography (CT),magnetic resonance imagine (MRI), or any other volumetric imagingsystem. In the embodiment that uses the patient anatomical data,stimulation field 178 may be similar to an electrical field model, whichis discussed in detail in FIGS. 37, 39, 41, and 44. For example,stimulation field 178 may rely on tissue impedance models, fieldpropagation models, and the like. In some embodiments, stimulation field178 may be a representation of an electrical field, current density,voltage gradient, or neuron activation, applied to a generic humantissue or the anatomy of patient 12. In addition, the clinician may beable to switch between any of these representations when desired.

In field views 175 or 198, the user may move the field up/down usingvertical scroll bar 184 or some similar control device. As stimulationfield 176 moves up or down in response to the user input, programmer 174automatically selects appropriate electrode combinations to support thevertical movement of the stimulation field. For example, programmer 174may phase electrodes in and out as stimulation field 178 travels upwardor downward, reducing the stimulation energy delivered from someelectrodes as the stimulation field moves away from them, and increasingthe stimulation energy delivered by other electrodes as the filed movestoward them. Also, in FIG. 11, field view 175 may include arrows 182, orsimilar input media, that permit the user to transition betweendifferent electrode levels of the lead in cross-sectional view 180.

In addition, the user may rotate stimulation field 178 using horizontalscroll bar 186 or some similar control device. An arrow 188 may beprovided next to horizontal scroll bar 186 to indicate the orientationof the lead relative to an anatomical structure. In addition, arrows maybe provided in respective cross-section views 180A-D of field view 198to maintain orientation. As the user rotates stimulation field 178,programmer 174 automatically selects appropriate electrode combinationsto support the rotational movement of the stimulation field. As in thecase of vertical movement, rotational movement of stimulation field 178may be accomplished by gradually reducing the stimulation energydelivered to some electrodes as the stimulation field rotates away fromthem, and gradually increasing the stimulation energy delivered to otherelectrodes as the stimulation field rotates toward them. Side view 176and cross-sectional view 180 permit the user to observe movement ofstimulation field 178 from both an axial perspective and a rotationalperspective.

Advantageously, movement of stimulation field 178 using scroll bars 184,186 or similar input media permits the user to evaluate different fieldpositions without the need to manually select electrodes and manuallyenter parameter values. Instead, programmer 174 automatically selectselectrodes and parameter values in response to movement of stimulationfield 178 by the user. Although scroll bars 184, 186 are illustrated asexamples of input media for movement of stimulation field 178, othertypes of input media may be used. Examples include up/down arrows orside-to-side arrows, which may be presented on a touch screen or formedby buttons or keys on programmer 174.

As a further alternative, the user may select stimulation field 178 witha stylus, mouse, or other pointing device and drag the field upward,downward, or rotationally. In some embodiments, a mouse or otherpointing device may support left or right click functionality to performdifferent operations relative to stimulation field 178. With a stylus, afirst click on stimulation field 178 may initiate movement, draggingwith the stylus directs movement, and a second click may terminatemovement. In each case, programmer 174 responds to the specifiedmovement by automatically adjusting the electrode combination and thestimulation parameters to approximate the characteristics of thestimulation field 178 presented on the display. As the stimulationparameter values change, the size and shape of stimulation field 178presented on the display change. Similarly, as the electrode combinationchanges in terms of polarity or electrode selection, the size, shape ordirection of stimulation field 178 presented on the display changes. Inother embodiments, programmer 174 may utilize stimulation templates andselect the best fitting stimulation template set to a newly modifiedstimulation field 178. Stimulation templates will be discussed furtherin FIGS. 30-36. Programmer 174 may limit the rate of movement ofstimulation field 178. In other words, stimulation field 178 may only bemoved a certain number of steps per second within user interface 172, orany other user interface that allows the clinician to drag thestimulation field. This rate movement limit may prevent unnecessarycalculations or ensure patient comfort in real-time programmingembodiments.

In addition to moving stimulation field 178, user interface 172 maypermit the user to perform one or more operations that result inreconfiguration of the stimulation field. For example, the user mayclick on a border, i.e., an outer perimeter, of stimulation field 178,and drag it inward or outward to resize the stimulation field. Resizingby enlarging or shrinking stimulation field 178 in user interface 172results in an increase or decrease in amplitude, pulse width or pulserate of the stimulation energy. In some embodiments, enlarging orshrinking stimulation field 178 also may result in selection ordeselection of electrodes included in the existing electrodecombination. In either case, programmer 174 adjusts the electrodecombination and/or parameter values in response to the enlargement orshrinkage of stimulation field 178 by the user.

When a user clicks on stimulation field 178 border and drags it, theentire stimulation field may be expanded in two dimensions in equalproportions. Alternatively, stimulation field 178 may expand only in thedirection in which the user drags the stimulation field. For example,horizontal dragging of the field perimeter to enlarge stimulation field178 may result in overall enlargement of the stimulation field, keepingthe vertical to horizontal aspect ratio constant. Alternatively,horizontal dragging may result only in horizontal expansion, leaving thevertical dimension constant. The application of a constant or varyingaspect ratio may be specified by a user as a user preference.Alternatively, programmer 174 may provide different aspect ratio modeson a selective basis for expansion and shrinkage of stimulation field178.

To enlarge or shrink stimulation field 178, the user may simply click onthe stimulation field border. Alternatively, the user may click on agrow/shrink button 190 as shown in FIGS. 11 and 12, and then click onthe border of stimulation field 178 to drag it inward or outward andthereby adjust the size of the stimulation field. In response,programmer 174 automatically reconfigures the electrode combinationand/or stimulation parameter values to approximate the resizedstimulation field. As will be described, other field adjustmentfunctions such as spread/focus button 192 and split/merge button 194 maybe provided by user interface 172. In each case, the user changesstimulation field 178 by simply changing the representation of thestimulation field on field view 175 or 198, thereby avoiding the need tomanually select electrodes and parameter values. However, the user mayselect “electrode view” at any time to return the electrode view screen,if desired. In some of these embodiments that allow the physician toenlarge, shrink, merge, or split stimulation field 178, programmer 174may employ the use of stimulation templates, as will be furtherdiscussed herein.

FIG. 13 illustrates selection of the grow/shrink feature by the user.User interface 199 is an embodiment of user interface 98, similar toother user interfaces herein, and is provided by a programmer 200. Inthe example of FIG. 13, the user expands the representation ofstimulation field 204A by clicking and dragging on the field perimeterafter selecting grow/shrink button 214 In particular, the user expandsthe stimulation field from stimulation field 204A to stimulation field204B. User interface 199 shows the expansion of the stimulation field inside view 202 as well as in cross-sectional views 206C, 206D thatinclude electrodes in the electrode combination that produces thestimulation field. As shown in FIG. 13, the shape of stimulation field204B in the cross-sectional views 206C, 206D is somewhat different asstimulation field 204A-B may be sized differently at different electrodelevels of the lead.

FIG. 14 illustrates user interface 199 of FIG. 13 upon vertical movementof stimulation field 216 instead of using scroll bar 210. Initially,stimulation field 216 is produced by an electrode combination positionedat levels 3 and 4 of the lead. The user moves stimulation field 216upward by dragging the block in the scroll bar upward. In response,programmer 200 moves the stimulation field 216 upward so that it isproduced by an electrode combination positioned at electrode levels 2and 3 of the lead. The movement of stimulation field 216 is visible notonly in side view 202, but also in cross-sectional views 206, which alsoshow the stimulation field changing between electrode levels as it movesupward. For example, stimulation field 216 is initially shown incross-sectional views 206C, 206D, corresponding to electrode levels 3and 4, and then moves to cross-sectional views 206B, 206C.

FIG. 15 generally corresponds to FIG. 14, but illustrates rotationalmovement of stimulation field 218. In the example of FIG. 15, a usermoves the horizontal scroll bar 212 to rotate stimulation field 218around the circumference of the lead. As shown in FIG. 15, the movementof stimulation field 218 is from left to right in side view 202 andcounter-clockwise in cross-sectional views 206A-D. Again, programmer 200responds to the rotational input entered by the user and automaticallyreconfigures the electrode combination and the stimulation parametervalues to approximate stimulation field 218.

In the simple illustration of FIG. 15, stimulation field 218 rotatesfrom electrodes at one set of angular positions to the electrodes at thenext set of angular positions. In this example, the electrodes formquadrants, and stimulation field 218 moves from one quadrant to the nextin a counter-clockwise direction in response to user input. However, therotational movement need not span an entire quadrant. In some cases, theuser may move stimulation field 218 such that it extends across adjacentquadrants, and programmer 200 adjusts the stimulation energy deliveredby both quadrants to approximate the position of the stimulation field218.

Rotational movement of stimulation field 218 is achieved by horizontalscroll bar 212, or other suitable input media, but rotational movementof the side and cross-sectional views may be accomplished by arrows 208.In particular, the user can press the left or right arrow 208 to rotateside view 202 in the pertinent direction and thereby view electrodesthat otherwise are not visible in the two-dimensional representation ofthe lead.

FIG. 16 corresponds substantially to FIGS. 11-15, but illustratesselection of a spread/focus command. Upon selection of the spread/focuscommand 224, the user may add additional electrodes to the currentelectrode combination, i.e., spread, or remove electrodes from thecurrent electrode combination, i.e., focus. Upon selection of thespread/focus command 224, user interface 199 may display plus (+) andminus (−) input buttons. Using the plus/minus buttons 222, userincreases or decreases, respectively, the number of electrodes in thecurrent combination, thereby spreading or focusing stimulation field220. The spreading and focusing may generally be configured to enlargeor shrink stimulation field 220 by addition or subtraction ofelectrodes, but preserve the vertical/horizontal/angular aspect ratiosof the stimulation field.

The spread/focus command 224 may result in changes in the stimulationparameter values. For example, when stimulation field 220 spreads, theamplitude for each electrode may be reduced such that the overallamplitude remains substantially the same. Similarly, upon focusingstimulation field 220 to a smaller number of electrodes, the amplitudefor each electrode may be increased. Alternatively, or additionally,pulse rate or pulse width may be increased or decreased as need toapproximate the stimulation field specified by the user.

FIG. 17 substantially corresponds to FIG. 13, but illustrates bothvertical movement of stimulation field 226 using vertical scroll bar 210and growing of the field from initial stimulation field 226B to anexpanded stimulation field 226A. In particular, stimulation field 226 ismoved upward from electrode levels 3 and 4 (FIG. 13) to electrode levels2 and 3, and expanded from field 226B to stimulation field 226A, all ofwhich is visible in both side view 202 and cross-sectional views206A-206D. When a user selects grow/shrink button 214, plus (+) andminus (−) input buttons or other media may be displayed by programmer 20to permit selective growing or shrinking of the stimulation field 226.

FIG. 18 illustrates a split/merge function in which user interface 199permits a user to split a field into two separate fields or merge twoseparate fields into a single field. For example, to split a field, theuser may click on the split/merge button 232 once, in which caseprogrammer 200 divides the electrode combination into two separateelectrode combinations and apportions parameter values between theelectrode combinations to apply two distinct stimulation fields 228 and230. Upon clicking split/merge button 232 twice, programmer 200 rejoinstwo or more separate electrode combinations and reconfigures stimulationparameters to form a single electrode combination that delivers a singlestimulation field.

FIG. 19 illustrates an example embodiment in which user interface 234permits the user, particularly the physician, to specify “keepout”regions in the electrode view. User interface 234 is an embodiment ofuser interface 98 and programmer 236 is an embodiment of programmer 19.For example, the physician may mark individual electrodes with an X onside view 238 and cross-sectional views 240A-D to specify thatprogrammer 236 should not change settings for those electrodes. In somecases, the keep out electrodes may be near a sensitive anatomicalstructure. Accordingly, it may be desirable to prevent the physician orthe patient from delivering stimulation via those electrodes. As anotherexample, it may be desirable to prevent modification of stimulationsettings associated with a particular electrode or set of electrodes sothat a minimum or baseline level of stimulation is always delivered tothe patient. In DBS, for example, sudden cessation of stimulation maycause adverse side effects. In other embodiments, the keepout regionsmay apply to ranges of stimulation parameter values, either globally oron an electrode-by-electrode basis. Such ranges may be specified usingamplitude, pulse width and frequency controls illustrated in FIG. 19, orother similar control boxes for these stimulation parameters provided bya pop-up or the like. Alternatively, specific electrodes may be markedas keepout regions when an electrode is deemed unsafe for stimulationtherapy. Unsafe electrodes may be determined by initial or periodicimpedance tests of each electrode in which the impedance is above orbelow normal operating limits.

FIG. 20 is an example of a user interface presented by the programmer aspart of a guided programming session. In this example, programmer 248automatically selects or automatically proposes electrode combinationsfor evaluation by the user with user interface 246. Each time the userclicks on the “Next” button, programmer 248 presents another electrodecombination. Programmer 248 may automatically select the electrodecombination or present a prompt for user approval indicating that theelectrode combination should be selected. User interface 246 is anembodiment of user interface 98 and programmer 248 is an embodiment ofprogrammer 19.

For each electrode combination, the user may manually adjust parametervalues or access the field view to manipulate the field. If a particularelectrode combination is perceived to be efficacious, the user may clickon the mark button. In response, programmer 248 records the electrodecombination and associated parameter settings in the efficacyinformation 96 in memory 90 of FIG. 5 so that the user can lateridentify and retrieve programs that were observed to support therapeuticefficacy. In addition, programmer 248 may record user feedbackinformation from each electrode combination in the form of subjectiveand/or objective feedback on therapy efficacy.

FIG. 21 generally corresponds to FIG. 6, but user interface 256 ofprogrammer 258 presents two leads with associated side andcross-sectional views. User interface 256 shown in FIG. 21 may beuseful, for example, in presenting combinations of multiple leads forbi-lateral DBS, spinal cord stimulation or other therapeuticapplications. Arrows 268, 270, or similar input media, may permit theuser to rotate side views 260 and 264 and cross-sectional views 262A-Dand 266A-D to better observe the selected electrode combination. Thefield view may be selected to observe representations of stimulationfields produced by the selected electrode combination. User interface256 is an embodiment of user interface 98 while programmer 258 is anembodiment of programmer 19.

FIGS. 22-25 are flow diagrams illustrating example operation of aprogrammer. Although described with reference to programmer 19 of FIG. 5and user interface 98, the techniques may be employed by any of theexample programmers and user interfaces described herein. FIG. 22generally illustrates a process for selecting electrode combination in alead having a complex electrode array geometry. A user selects an axialelectrode position (272), e.g., using the electrode view of userinterface 98 or any embodiments thereof as described herein. The axialelectrode position identifies an electrode level at one of several axialpositions along the length of a distal portion of the lead. Uponidentifying an axial position, the user selects an angular electrodeposition (274). The angular electrode position may selected by clickingon an electrode at the desired electrode level, either via the side viewor the cross-sectional view. In the cross-sectional view, any of theelectrodes may be readily selected. In the side view, it may benecessary to rotate the lead within user interface 98 to view a desiredelectrode to be selected. In some embodiments, a concentric axial viewmay be used instead of the cross-sectional view or an unwrapped 2D arrayview may be used instead of the side and cross-sectional view.

For one or more electrodes, specified by axial and angular position, theuser selects the polarities of the electrodes such that the electrodesare designated as either a cathode or an anode (276). Programmer 19defines the electrode combination (278) based on the selected axialpositions, angular positions and polarities, and evaluates the electrodecombination by applying stimulation to patient 12 via the electrodecombination using parameter values selected or approved by the user(280). Upon application of the stimulation, the user may enter efficacyinformation, which programmer 19 records in memory 90 for lateridentification and retrieval (282).

FIG. 23 shows a process for selecting and evaluating electrodecombinations on a lead having a complex electrode array geometry. Asshown in FIG. 23, via user interface 98 or other similar user interfaceas described herein, the user starts the selection process (284) andselects initial axial and angular positions of electrodes to form aninitial electrode combination (286). The axial and angular positions mayresult in selection of multiple electrodes at a single axial electrodelevel or two or more different axial electrode levels. The initialelectrode combination may be manually selected by the user, orrecommended by programmer 19, e.g., according to a predetermined ordynamically generated evaluation sequence.

Upon selection of the initial electrode combination, programmer 19instructs implantable stimulator 20 to apply stimulation energy via theselected combination. The user evaluates the electrode combination (288)and records efficacy information via user interface 98 (290). Theefficacy information may be obtained by observation of patient 12 or byverbal or other feedback provided by the patient. If not all permittedangular positions have been evaluated (292), programmer 19 rotates theangular position of the electrode combination (294), e.g., clockwise,and evaluates the next electrode combination (288).

This process may continue iteratively until all permitted angularpositions have been evaluated. An angular position is “permitted” in thesense that the user is permitted to evaluate it. In some cases, aphysician may restrict some angular positions from evaluation, e.g., bydesignating them as keepout regions if adverse side effects could resultdue to stimulation of sensitive anatomical structures.

Once all angular positions have been exhausted, i.e., all permittedelectrodes at different angular positions around the circumference ofthe lead have been tested (292), programmer 19 translates the axialposition of the electrode combination upward or downward on the lead(296). At each axial position, programmer 19 repeats the process ofevaluating different angular positions. The process ends when allpermitted axial positions have been evaluated (298), or when a userotherwise wants to quit the process by stopping the process (300).

FIG. 24 illustrates a process similar to FIG. 23. However, axialpositions are evaluated for different angular combinations. Hence, theprocess of FIG. 24 represents the opposite of the process of FIG. 23. InFIG. 24, via user interface 98 or other user interface described herein,the user starts the process (302) by selecting initial axial and angularpositions of electrodes to form an initial electrode combination (304).Upon selection of the initial electrode combination, a programmer, e.g.,programmer 19, instructs implantable stimulator 20 to apply stimulationenergy via the selected combination. The user evaluates the electrodecombination (306) and records efficacy information (308). Again, theefficacy information may be obtained by observation of patient 12 or byverbal or other feedback provided by the patient. If not all permittedaxial positions have been evaluated (310), programmer 19 translates theaxial position of the electrode combination, e.g., upward or downward(306), and evaluates the next electrode combination (306).

This process may continue iteratively until all permitted axialpositions have been evaluated. An axial position is “permitted” in thesense that the user is permitted to evaluate it. In some cases, as inthe example of FIG. 23, a physician may restrict some axial positionsfrom evaluation, e.g., by designating them as keepout regions if adverseside effects could result due to stimulation of sensitive anatomicalstructures.

Once all axial positions have been exhausted (310), i.e., all permittedelectrodes at different axial positions along the length of the leadhave been tested, programmer 19 rotates the angular position of theelectrode combination around the circumference of the lead (314). Ateach angular position, programmer 19 repeats the process of evaluatingdifferent axial positions (316). The process ends when all permittedangular positions have been evaluated (318).

FIG. 25 shows another process for evaluating electrode combinations on alead with a complex electrode array geometry. In the example of FIG. 25,the process starts (320) by selecting axial ring electrode combinations(322) and evaluating these electrode combinations made up of entirerings of electrodes disposed at different axial electrode levels. Inthis initial part of the process, programmer 19, or any other programmerdescribed herein, treats the lead as if it were a conventional lead withring electrodes. Alternatively, unipolar electrode rings may beactivated and evaluated in addition to or instead of bipolar electroderings.

Each electrode at a different angular position in a particular electrodelevel is activated simultaneously as if they formed a single ringelectrode. Programmer 19 selects two or more electrode “rings” andevaluates stimulation efficacy. Programmer 19 selects additional rings,e.g., moving up and down the lead, until a “good” combination is found.This process results in a coarse tuning of the stimulation. Then,programmer 19 evaluates different angular positions of electrodes withinthat combination to fine-tune the stimulation.

As shown in FIG. 25, programmer 19 first selects an axial ring electrodecombination. As an illustration, it is assumed that the lead includesfour axial electrode levels, each including four electrodes at differentangular positions around the lead circumference. An example of an axialring electrode combination is the combination of all electrodes atelectrode level 1 and all electrodes at another level such as electrodelevel 2, level 3 or level 4, producing, in effect, a combination of twoor more ring electrodes. Alternatively, programmer 19 may also

Programmer 19 directs the stimulator to deliver stimulation energy viathe selected axial ring electrode combination. The user evaluates theelectrode combination (324) and records efficacy information inprogrammer 19 (326). If not all permitted ring combinations have beenevaluated (328), programmer 19 shifts the axial ring combination upwardor downward on the lead, or otherwise selects a different axial ringcombination (330).

For example, programmer 19 may shift a ring combination of level 1 andlevel 2 downward to produce a new combination of level 2 and level 3.However, programmer 19 may be configured to explore other possiblecombinations. For example, programmer 19 may shift a ring combination oflevel 1 and level 2 to a combination of level 1 and level 3, then level1 and level 4, then level 2 and level 3, then level 2 and level 4, thenlevel 3 and level 4, and so forth.

Upon evaluating each axial ring electrode combination and recordingefficacy information, programmer 19 shifts to the next axial ringcombination if not all of the permitted ring combinations have beenevaluated. After all ring combinations have been evaluated (328),programmer 19 selects the best ring combination as a coarse tuningresult (332), and then proceeds to fine tune the stimulation byevaluating different angular combinations.

In particular, upon selection of the “best” ring combination in terms ofefficacy (or some other ring combination having at least acceptableefficacy), programmer 19 reduces the selected combination to a set ofelectrodes at one or more angular positions (334). For example, if theselected ring combination is a combination of all electrodes at levels 2and 3, the programmer next selects individual electrodes at differentangular positions in levels 2 and 3.

As an illustration, if the four electrodes in a level are numbered 1through 4, the programmer may start with an electrode combination oflevel 1, electrode 1 and level 3, electrode 1. Upon evaluating theelectrode combination (336) and recording efficacy information (338),programmer 19 selects another angular position with in the ringelectrode combination. For example, the programmer may rotate the fieldto an electrode combination of level 1, electrode 2, and level 3,electrode 2. The process continues until all permitted angular positionshave been evaluated (340). Then, the physician may stop the processor(342) and select one of the axial/angular electrode combinations to forma program for delivery of stimulation energy.

As a refinement to the process of FIG. 25, programmer 19 also mayevaluate a plurality of different stimulation parameter settings foreach axial ring electrode combination, each axial/angular combination,or both. In this manner, programmer 19 attempts to optimize theelectrode positions and the stimulation parameter values delivered viathe selected electrodes to provide overall efficacy.

Although the illustration above refers to the evaluation of individualelectrodes at different angular positions, e.g., level 1, electrode 1,and level 3, electrode 1, each level may have more than one electrodeactivated at a time. For example, programmer 19 may not only evaluateindividual angular positions, but also combinations of electrodes atangular positions. In particular, programmer 19 may evaluate acombination of axial level 1, electrodes 1 and 2 and axial level 3,electrodes 1 and 2, or any combination of electrodes in a given level,e.g., (a) 1 and 2, (b) 1 and 3, 1 and 4, (c) 2 and 3, (d) 2 and 4, (e) 3and 4, (f) 1, 2, and 3, (g) 1, 2 and 4, (h) 1, 3 and 4, (i) 2, 3, and 4,and so forth. In some embodiments, each evaluation of one or moreelectrodes may comprise evaluation of the electrodes as cathodes in abipolar configuration with one or more electrodes on the lead acting asan anode, or a monopolar configuration with an indifferent electrode,e.g., the housing of stimulator 20, acting as the anode.

FIG. 26 is a diagram illustrating ring-based selection of axialpositions on a lead having a complex electrode array geometry, asdescribed in FIG. 25. An initial electrode combination may include aring formed by all electrodes in a given level and all electrodes inanother level. In the example of FIG. 26, as shown in side view 348 andcross-sectional views 350A-D, all electrodes at different angularpositions in axial electrode level 3 are selected as “+” electrodes andall electrodes at different angular positions in axial electrode 4 areselected as “−” electrodes. Alternatively, unipolar electrode rings maybe selected, e.g., only one anode or cathode ring. The opposite pole maybe a specific electrode or the conductive housing of stimulator 12.

FIGS. 27 and 28 are diagrams illustrating selection of differentelectrode combinations on a lead having a complex electrode arraygeometry using guided evaluation sequences. The two-dimensional arrayshown in FIGS. 27 and 28 represents all of the axial and angularpositions of electrodes on a lead having four electrode levels and fourangular positions, resulting in a four-by-four array of possibleelectrodes.

FIG. 27 further illustrates the ring-based coarse tuning of stimulationdescribed above with respect to FIGS. 25 and 26. Programmer 19 will beused as an example in FIGS. 27 and 28; however, any programmer describedherein may be used in a similar manner. In FIG. 27A, programmer 19initially evaluates effective ring electrodes formed by electrodes atall angular positions in electrode levels 1 and 2. In FIG. 27B, theaxial ring combination is shifted to includes all electrodes in levels 2and 3. In FIG. 27C, the axial ring combination is shifted to include allelectrodes in levels 3 and 4.

Upon selecting one of the axial ring combinations, e.g., levels 2 and 3,programmer 19 rotates among different angular electrode positions tofine tune the electrode combination. In FIG. 27D, programmer 19initially evaluates electrodes 2A and 3A, i.e., the electrodes in thefirst angular position in levels 3 and 4. In FIGS. 27E and 27F,programmer 19 rotates the field from 2A-3A to 2B-3B (FIG. 27E) and thenfrom 2B-3B to 2C-3C (FIG. 27F).

Evaluation involves transmission of a program or instructions to thestimulator defining the electrode combination and associated parametervalues, and activation of the stimulator to deliver stimulation energyaccording to the electrode combination and parameter values. Thisprocess shown in FIGS. 27A-27F may continue until several angularelectrode combinations are evaluated for the selected axial ringcombination. Again, the angular electrode combinations may includemultiple electrodes in a given electrode level, and may explore allcombinatorial possibilities or a subset of the possibilities.Ultimately, the physician selects one or more of the axial-angularcombinations based on the evaluation and perceive efficacy.

FIGS. 28A-28F illustrate another guided evaluation sequence in whichprogrammer 19 or the user specifies an initial axial/angular electrodecombination, and the programmer selects additional electrodes to “orbit”around the initial electrode combination. In the example of FIG. 28A, aninitial electrode combination of 2B−, 2C+ and 3C− is selected andevaluated by activating stimulation according to the specified electrodecombination. Various stimulation parameter values may be adjusted andtested for the electrode combination. The user may record efficacyinformation via programmer 19.

Then, programmer 19 fine-tunes the electrode combination by “orbiting”around it. In the example of FIGS. 28A-28F, the 2C+ electrode serves asan anchor point, while the—electrodes are rotated around it. Inparticular, programmer 19 shifts from the initial combination (2B−, 2C+and 3C−) to combinations of 2C+, 3B−, 3B−(FIG. 28B), 2C+, 2D−, 3C− (FIG.28C), 1C−, 2C+, 2D+(FIG. 28D), and 1C−, 2B−, 2C+ (FIG. 28E). In theexample of FIG. 28F, upon orbiting around all positions of the electrodecombination centered at 2C+, programmer 19 moves the anchor point to 3C+and starts with 3B− and 4C− as the next initial electrode combinationfor the orbit process. While an anode is used as an example, a cathodemay also be used as the anchor point in a similar manner.

The orbit process may continue across several different anchor points.For each anchor point and associated orbit, programmer 19 directs thestimulator to deliver stimulation via the specified electrodecombination, permitting the user to evaluate and record stimulationefficacy. In some embodiments, the efficacy recorded for a particularelectrode combination may be used to dynamically guide the orbit or theselection of anchor points. If anchor points 4A and 4B produce poorefficacy, for example, programmer 19 may avoid continued orbits in thoseareas of the electrode array geometry, and instead select differentanchor points further away from those points.

FIG. 29 is a diagram illustrating a user interface present two sideviews 362 and 364 of one lead having a complex electrode array geometry.In the example of FIG. 29, user interface 358 of programmer 360 presentsside view 362 and 364 of the two different sides of a single lead, sothat all electrodes are simultaneously visible. For example, side view362 shows a first 180 degree side of the lead while side view 364 showsa second 180 degree side of the lead. In some embodiments, side views362 and 364 may be rotated to change the perspective of the lead. Theelectrodes may be selected using a stylus of other pointing device. Insome embodiments, an orientation arrow 366 may be added to illustrateorientation of the lead relative to an anatomical structure. Userinterface 358 is an embodiment of user interface 98 and programmer 360is an embodiment of programmer 19.

FIGS. 30A-D are conceptual diagrams of example cross-sections ofstimulation templates stored for electrode combinations of two adjacentlevels of a complex electrode array geometry. A stimulation template isa predetermined volumetric stimulation field that programmer 19 can useto match to a desired stimulation field from the clinician. The processof selecting one or more stimulation templates to generate stimulationparameters that fit the user defined stimulation field may be lesscomputationally intensive for programmer 19 than using multipleequations or lookup tables to generate the stimulation parameters. Thestimulation template may be a representation of an electrical field orother electrical stimulation related characteristic, e.g., currentdensity, voltage gradient, or neuron activation, applied to a generichuman tissue. In addition, the clinician may be able to switch betweenany of these representations when desired.

Cross-sections of example stimulation templates are provided toillustrate possible fields around the circumference of implanted lead14. FIGS. 30A-D illustrate possible cross-sections of stimulationtemplates of an electrode of one electrode level paired to anotherelectrode at another electrode level at the same circumferentialposition. Even through only cross-sections of stimulation templates areshown, they will be referred to as a stimulation template forsimplicity. In some embodiments, programmer 19 may utilize stimulationtemplates to reduce the processing tasks of generating stimulationparameters for therapy. In this manner, programmer 19 may select one ormore stimulation templates that best match the desired stimulationfield. If only one electrode is chosen, at least one other electrodeabove or below the selected electrode must also be used to create thestimulation template. In other embodiments, similar stimulationtemplates may be created with complex electrode array geometriesutilizing more or less than 4 electrodes in a give electrode level. Thestimulation template may not indicate the exact shape of the resultingstimulation field, as the tissue adjacent to the electrode may affectthe propagation of the electrical current.

FIG. 30A shows electrode 370 and corresponding cross-section ofidealized stimulation field 372 that creates stimulation template 368.FIG. 30B shows electrode 376 and corresponding cross-section ofidealized stimulation field 378 that creates stimulation template 374.FIG. 30C includes stimulation template 380 which is created by electrode382 and cross-section of idealized stimulation field 384 adjacent to theelectrode. FIG. 30D indicates that stimulation template 386 is createdfrom electrode 388 and cross-section of idealized stimulation field 386.The actual shape of each stimulation template may vary depending uponthe surrounding tissue to the implanted lead. However, system 10 may usethe idealized stimulation templates as approximate stimulation templatesfor the purpose of matching the best template to the user definedstimulation field. For all stimulation templates, programmer 19 mayadjust the current amplitude or voltage amplitude to alter the size ofthe stimulation template to cover the desired stimulation field from thephysician. In addition, programmer 19 may combine any of the stimulationtemplates 368, 374, 380 and 386 to stimulate tissue at desired locationsaround the lead. In some embodiments, the physician may have manualcontrol to change the polarity of one or more electrode of a stimulationtemplate such that the stimulation of the stimulation template set maybe slightly changed to affect the therapy provided by the stimulationtemplate set.

FIGS. 31-36 include schematic diagrams illustrating example userinterfaces that present stimulation templates to the user. FIG. 32illustrates example definition of a stimulation field. As shown in FIG.31, user interface 392 presents a user defined stimulation field viewthe user via programmer 394. User interface 392 is an embodiment of userinterface 98 and programmer 394 is an embodiment of programmer 19. Userinterface 392 allows the user to define stimulation field 398 byoutlining the stimulation field on side view 396, cross-sectional view400, or both. In addition to outlining stimulation field 398, thephysician may drag any portion of the outline to change the shape orsize of the field. Stimulation field 398 may represent the volume ofpatient 12 tissue around the implanted lead 14 to which the user desiredto apply an electrical field from stimulator 20. In other embodiments, astimulation field may be defined on any type of cross-sectional,concentric, or unwrapped view of lead 14.

As described above, the user may rotate side view 396 to view otherelectrodes of the lead or move stimulation field 398 with a slider orother input media. Amplitude adjustment mechanism 404 may be used toincrease or decrease the size of stimulation field 398 by changing theamplitude of the stimulation therapy to be delivered to patient 12. Thephysician may also grab and drag stimulation field 398 to manipulate thesize and shape of the field. In other embodiments, user interface 392may present adjustment mechanisms for pulse width, pulse rate, or anyother parameters. The user may use orientation marker 402 to identifywhere the lead position is with respect to known anatomical structuresadjacent to the implanted lead 14. The user may use arrows 406 to changecross-sectional view 400 to another axial electrode level of the lead.When the physician is satisfied with stimulation field 398, thephysician may select the select template button 410 to request thatprogrammer 394 find the best stimulation template set and show thetemplate set (described in FIGS. 33-35). In addition, the user mayaccess other options provided by user interface 392 by selecting menu408 or switch stimulation field view to the electrode view by selectingelectrode view button 412.

FIG. 32 provides a flow diagram that illustrates an example method fordefining a stimulation field as discussed above with respect to FIG. 31.In programmer 394, the physician may interact with user interface 392 toenter the stimulation field view (413). The physician then outlinesstimulation field 398 on side view 396 with a stylus or other pointingdevice (415). Next, the physician outlines stimulation field 398 oncross-sectional view 400 to give the stimulation field another dimensionthat allows programmer 394 to generate the volumetric stimulation field398 around the lead. If the physician desires to further definestimulation field 398 in other electrode levels (419), the physicianselects a different cross-sectional view 400 and proceeds to define thefield (417). Once the physician has completed defining stimulation field398, the physician requests that programmer 394 generates stimulationparameters (421). As will be described below, the generation ofparameters may include the selection of stimulation templates. Howeverother equation sets, lookup tables, matrices, or other method may beemployed for programmer 394 to select appropriate stimulation parametersfrom stimulation field 398.

In some embodiments, the physician may first define stimulation field398 on cross-sectional view 400 prior to side view 398. However, bothoutlines are necessary for programmer 394 to generate the volumetricstimulation field. Stimulation field 398 is the desired area that thephysician would like to stimulate with therapy. In other embodiments,the physician may be able to outline or otherwise define and manipulatethe stimulation field in the field view 175 of FIG. 11 (or other similarembodiment). Therefore, a separate stimulation field view may not berequired for a physician to request that the programmer automaticallygenerate stimulation parameters from a defined stimulation field.

FIG. 33 illustrates user interface 392 that provides a template view tothe user via programmer 394. Based upon stimulation field 398 that theuser has defined in FIG. 32, programmer 394 creates a best fitstimulation template set 414 from volumetric stimulation templatesstored in memory 90 of the programmer. Stimulation template set 414 isthe best fit stimulation template set for stimulation field 398 becauseit covers the majority of the stimulation field without extending beyondthe edge of the stimulation field. This preference may be beneficialbecause side effects may be much less desirable than completelyeliminating the condition of patient 12. Alternatively, the best fitstimulation template set 414 may completely cover stimulation field 398such that the entire desired volume of tissue is affected by thestimulation therapy.

The user may alter the size of stimulation template set 414 by draggingstimulation field 398 to a different shape, moving the stimulation fieldto a different location on the lead, or changing the magnitude ofamplitude 404. Programmer 394 may create a new stimulation template setafter stimulation field 398 changes enough that a new stimulationtemplate set provides a better fit. As described above, stimulationtemplate set 414 is representative of a stimulation parameter set thatstimulator 20 uses to deliver stimulation therapy to patient 12. If theuser is satisfied with stimulation template set 414, the user may selectaccept template button 410 to save the stimulation template set andtransmit the associated stimulation parameters to stimulator 20 fortherapy.

FIG. 34 illustrates user interface 416 which presents side view 420 andconcentric axial view 426 to the user via programmer 418. User interface416 is substantially similar to user interface 392, but user interface416 provides concentric axial view 426 instead of cross-sectional view400. The user has defined stimulation field 422 on side view 420 andprogrammer 418 has created stimulation template set 424 to fit thestimulation field. The user may alter stimulation field 422 or move thestimulation field, and in response programmer 418 may create a newstimulation template set. In some embodiments, programmer 418 presentsplus and minus signs on the electrodes associated with stimulationtemplate set 424. The physician may decide to change the polarity of oneor more electrodes to modify the effective stimulation therapy topatient 12. In the change in polarity alters the shape or size ofstimulation template set 424, programmer 418 may change therepresentation of the template set accordingly.

In some embodiments, the user may define stimulation field 422 onconcentric axial view 426 in addition to side view 420. The stimulationfield may be shown to cover each respective electrode of concentricaxial view that would be used for therapy. In addition, stimulationtemplate set 424 altered as the user determines that stimulationtemplate set 424 is not sufficient to deliver efficient therapy topatient 12. When the user determines that stimulation template set 424is ready to be used for stimulation therapy, the user may select accepttemplate button 432 to transmit the stimulation parameters of thestimulation template to stimulator 20.

FIG. 35 illustrates user interface 436 which presents unwrapped 2D arrayview of the lead to the user via programmer 438. User interface 436 issubstantially similar to user interface 392, but user interface displaysthe electrodes of the lead in a different manner. In the example of FIG.35, the user has defined stimulation field 444 on unwrapped 2D arrayview 440 to fir the stimulation field. The user may alter stimulationfield 444 or move the stimulation field such that programmer 438 willchange stimulation template set 446 to match the new stimulation field.The user may also use orientation marker 442 to recognize theorientation of the lead to the anatomical structures of patient 12. Whenthe user is satisfied with stimulation template set 446, the user mayselect accept template button 450 to accept the stimulation template setand transmit the corresponding stimulation parameters to stimulator 20for therapy.

FIG. 36 illustrates an exemplary template menu of any user interfaces392, 416, and 436. As shown in the example of FIG. 36, template menu 454is presented to the user when the user presses menu 408. Template menu454 includes modify stimulation field button 458 which allows thephysician to modify stimulation field 398, select polarity button 460 tochange the polarity of each electrode, new template set button 462 whichforces programmer 394 to select a new stimulation template set, andmanual selection button 464 which allow the user to return to theelectrode view to manually select stimulation parameters in userinterface 392. The user may close template menu 454 by selecting exit456. In other embodiments, template menu 454 may provide differentoptions to the user to enter any other mode offered by programmer 394.

FIG. 37 is a flow diagram illustrating example operation of theprogrammer for selecting a stimulation template set. User interface 392and programmer 394 is used herein as an example, but any programmer maybe used in the example of FIG. 37. As shown in FIG. 37, user interface392 displays the stimulation field view to the user (466). Userinterface 468 next receives stimulation field input from the user (468).The stimulation field input may include outlining the stimulation fieldon one or more views of the lead or altering a stimulation fieldproduced manually from an electrode view or automatically in thestimulation field view. Programmer 394 calculates the error between thestimulation field and the available stimulation templates (470). Theerror may be calculated as the difference in volume between the definedstimulation area and the volumetric stimulation template set, divided bythe defined stimulation area. However, other methods of calculating theerror may be used to identify the “fit” of the stimulation template setto the defined stimulation field. From the error calculations,programmer 394 selects the stimulation template set with the smallesterror between the templates and the stimulation field (472). Typically,the template set must remain within the defined stimulation area toprevent stimulation of non-target tissue. However, some embodiments, mayallow stimulation template sets that best fit the stimulation area evenwhen a portion of the stimulation template set stimulates tissue outsideof the stimulation field.

If the best fit stimulation template set error is greater than apredetermined threshold (474), user interface 392 will provide thestimulation template set to the physician with an error messageindicating that the template set exceeds the error (476), and in someembodiments of user interface 392, programmer 394 may force thephysician to modify the stimulation field. If the best fit stimulationtemplate set error is less than the predetermined threshold (474), userinterface 392 provides the stimulation template set to the physician(478). If the physician does not accept the created stimulation templateset (480), user interface 392 will again receive stimulation field input(468). If the physician wants to accept the stimulation template set fortherapy (480), programmer 394 stores the stimulation parameters from thestimulation template set (482). Programmer 394 then delivers thestimulation parameter sets to stimulator 20 which delivers thestimulation therapy to patient 12 (484).

FIGS. 38-44 are schematic diagrams illustrating example user interfacesthat present electrical field models and activation field models to theuser. FIG. 38 illustrates an example user interface 486 that displays afield view to the user via programmer 488. User interface 486 is anembodiment of user interface 98 and programmer 488 is an embodiment ofprogrammer 19. User interface 486 displays side view 490 andcross-sectional view 496 of the implanted lead, and the user definesstimulation field 492 on the side and cross-sectional views. Fromstimulation field 494, programmer 488 generates stimulation parametersfor therapy and generates an electrical field model that estimates theelectrical field of the therapy. The electrical field model is displayedas electrical field 494, within stimulation field 492. In otherembodiments electrical field 494 be a representation of anotherelectrical stimulation related characteristic, e.g., current density, orvoltage gradient. In addition, the clinician may be able to switchbetween any of these representations when desired.

Electrical field 494 represents where the electrical current willpropagate from the implanted lead 14 within brain 18, as tissuevariation within brain 18 may change the electrical current propagationfrom the lead in some directions. The variations in electrical fieldpropagation may affect the ability of the therapy to actually treat adesired structure or cause a side-effect. The horizontal and axial viewsof electrical field 494 illustrated in FIG. 38 are 2D slices of thevolumetric electrical field model created by programmer 488. Programmer488 utilizes the patient anatomy data with electrical field modelequations that define electrical current propagation. More specifically,programmer 488 may apply the electrical field model equations thatdefine how the electrical field is propagated from an origin locationaway from the origin. The electrical field equations require thephysical tissue characteristics of the tissue adjacent lead 14, which isincluded in the patient anatomy data set. From this information,programmer is able to generate the estimated electrical field 494 thatwill be produced in therapy. Electrical field 494 may differ from thefield view in FIG. 11 because the field view only includes generaltissue characteristics not specific from patient 12. In otherembodiments, the electrical field equations may utilize matrices orother mathematical model of the electrical field. In this manner,electrical field 494 can be estimated and modeled for the physician.Accordingly, the physician may be able to increase or decrease theamplitude of the stimulation parameters with amplitude 502 to change thesize and possibly shape of electrical field 494 or directly manipulateelectrical field 494. If the user is satisfied with electrical field494, the user may select accept field button 506 to transmit thestimulation parameters to stimulator 20 and bring therapy.

FIG. 39 is similar to FIG. 38 and illustrates an example user interface486 that displays an activation field view to the user via programmer488. From the defined stimulation field 492 on the side view 490 andcross-sectional view 492, programmer 488 generates stimulationparameters for therapy and generates an activation field model basedupon the electrical field model of FIG. 38 and a neuron model thatestimates which neurons within the electrical field model will beactivated by the voltage of the electrical field during therapy. Theneuron model may be a set of equations, a lookup table, or another typeof model that defines threshold action potentials of particular neuronsthat make up the anatomical structure, as defined by the patient anatomydata, affected by the electrical field. If the voltage or currentamplitude of the electrical field is above the threshold of any neuronwithin the electrical field, that neuron will be activated, e.g., causea nerve impulse. The activation field model is displayed as activationfields 510 and 512, within stimulation field 492.

Activation fields 510 and 512 of the activation field model indicate tothe user where neurons around the lead will be activated from thestimulation therapy. Due to changes in electrical current propagationand voltage thresholds to activate a neuron, the activation of neuronsmay vary with the location of tissue around the lead. Some neurons mayactivate further from the lead with smaller voltages while other neuronsmay only be activated close to the lead because of a high voltagethreshold. These differences in neurons may account for separateactivation fields 510 and 512 within a contiguous stimulation field 492.The user may view cross-sections at other electrode levels with arrows500. In addition, the user may increase or decrease the size and/orshape of activation fields 510 and 512 by changing the amplitude withamplitude 502 or directly manipulate the activation fields toautomatically modify the stimulation parameters. Once the user issatisfied with activation fields 510 and 512, the user may select acceptfield 506 to transmit the corresponding stimulation parameters tostimulator 20 for therapy.

FIG. 40 illustrates an example user interface 514 that displays anelectrical field view to the user via programmer 516. User interface 514displays side view 518 and concentric axial view 524 of the implantedlead, and the user defines stimulation field 520 on the side view. Fromstimulation field 520, programmer 516 generates stimulation parametersfor therapy and generates an electrical field model that estimates theelectrical field of the therapy, similar to programmer 488 of FIG. 38.While electrical field 522 is not shown over concentric axial view 524,other embodiments may include the electrical field displayed over theappropriate electrodes of the concentric axial view. Once the user issatisfied with electrical field model, the user may select accept fieldbutton 532 to begin stimulation therapy. Stimulation field 520 is notshown in user interface 514 because the stimulation field may notaccurately show the field to the physician. However, in someembodiments, stimulation field 520 may also be shown over concentricaxial view 524 to approximate the field in the axial dimension.

FIG. 41 is similar to FIG. 40 and illustrates an example user interface514 that displays an activation field view to the user via programmer516. Activation field view of FIG. 41 may be substantially similar toFIG. 39 with respect to generating and displaying the activation fieldmodel. From the defined stimulation field 520 on the side view 518,programmer 516 generates stimulation parameters for therapy andgenerates an activation field model based upon the electrical fieldmodel of FIG. 40 and a neuron model that estimates which neurons withinthe electrical field model will be activated by the voltage of theelectrical field during therapy. The activation field model is displayedas activation fields 536 and 538, within stimulation field 520. Whileactivation fields 536 and 538 are not shown over concentric axial view524, other embodiments may include the activation fields displayed overthe appropriate electrodes of the concentric axial view for a differentperspective of the activation field model. Once the user is satisfiedwith activation fields 536 and 538, the user may select accept field 532to transmit the corresponding stimulation parameters to stimulator 20for therapy.

FIG. 42 illustrates an exemplary user interface 540 that displays anelectrical field view to the user via programmer 542. User interface 542is an embodiment of user interface 486 and programmer 542 is anembodiment of programmer 488. User interface 540 displays unwrapped 2Darray view 544 and orientation arrow 546 of the implanted lead, and theuser defines stimulation field 548 on the unwrapped 2D array view. Fromstimulation field 548, programmer 542 generates stimulation parametersfor therapy and generates an electrical field model that estimates theelectrical field of the therapy, similar to programmer 488 of FIG. 38.In some embodiments, user interface 540 may allow the user to rotate orflip unwrapped 2D array view to view the profile of electrical field 550away from the electrodes of the lead. In other words, the physician maybe able to view the distance away from the electrodes that theelectrical field will propagate. Once the user is satisfied withelectrical field model, the user may select accept field button 556 tobegin stimulation therapy.

FIG. 43 is similar to FIG. 42 and illustrates an example user interface540 that displays an activation field view to the user via programmer542. The activation field view of FIG. 43 may be substantially similarto FIG. 39 with respect to generating and displaying the activationfield model. From the defined stimulation field 548 on unwrapped 2Darray view 544, programmer 542 generates stimulation parameters fortherapy and generates an activation field model based upon theelectrical field model of FIG. 42 and a neuron model that estimateswhich neurons within the electrical field model will be activated by thevoltage of the electrical field during therapy. The activation fieldmodel is displayed as activation fields 560 and 562, within stimulationfield 560. Similar to FIG. 42, some embodiments of user interface 540may allow the user to rotate or flip unwrapped 2D array view 544 to viewthe profile of activation fields 560 and 562 away from the electrodes ofthe lead. Once the user is satisfied with activation fields 560 and 562,the user may select accept field 556 to transmit the correspondingstimulation parameters to stimulator 20 for therapy. While theactivation field model has been shown to include two separate activationfields, any number of activation fields may be produced from theelectrical field model and the neuron model. For example, one contiguousactivation field may be produced by the programmer or several smalleractivation fields may be produced. The examples of FIGS. 38, 40 and 42are merely examples of potential activation fields.

FIG. 44 illustrates an example field menu of any user interfaces 486,514, and 540. As shown in the example of FIG. 44, user interface 486presents field menu 561 to the user when the user presses menu 504.Field menu 561 includes modify stimulation field button 564 to redefinethe stimulation field, select polarity button 566 to alter the polarityof any electrodes, change field view button 568 to modulate betweenelectrical or activation field views, and manual mode button 570 whichallows the user to manually select the stimulation parameters in theelectrode view, e.g., FIG. 11. The user may close field menu 560 byselecting exit 563. In other embodiments, template menu 560 may providedifferent options to the user to enter any other mode offered byprogrammer 488.

In alternative embodiments, the electrical field model or activationfield model may be used in place of the generic field view 175 of FIG.11. For example, upon selection of electrodes in the electrode view, theprogrammer may generate the corresponding electrical field model oractivation field model and present one of these customized fields ofpatient 12 to the physician in place of the generic field view describedin FIG. 11. In addition, an electrical field view or activation fieldview may be applied to any side, cross-sectional, concentric axial, orunwrapped lead views described herein.

FIG. 45 is a flow diagram illustrating an example technique forcalculating and displaying the electrical field model of definedstimulation according to FIGS. 37, 39 and 41. As shown in FIG. 45, userinterface 486 receives patient anatomy data necessary for creating anelectrical field (572), as described in FIG. 38. Programmer 488 entersthe patient anatomy data in stored electrical field model equations orequation sets to satisfy anatomical variable (574). Programmer 488 nextcalculates the electrical field model from the data and equations (576).Once user interface 486 receives stimulation input from the physiciandefining the stimulation field (578), the electrical field may bedisplayed to the physician via the user interface (580). If thephysician desires to change the stimulation input (582), user interface486 receives a change in the stimulation input (578). If the physiciandoes not request a stimulation input change (582), user interfacecontinues to display the electrical field to the physician (580).

FIG. 46 is a flow diagram illustrating an example technique forcalculating and displaying the activation field model of definedstimulation according to any of FIG. 38, 40 or 42. As shown in FIG. 46,user interface 486 receives patient anatomy data indicative of theanatomy of patient 12 (584) and programmer 488 calculates the electricalfield model from the patient anatomy data (586). Programmer 488 thenretrieves the neuron model and fits the neuron model to the electricalfield (588). Programmer 488 then calculates the activation field modelbased upon the electrical field model and neuron model (590). Userinterface 486 then is able to receive stimulation input from thephysician defining the stimulation field (592). The resulting activationfield model is displayed by user interface 486 (594). If the physiciandesires to change the stimulation input (596), user interface 486receives stimulation input from the physician modifying the previousstimulation input (592). If the stimulation input does not need to bechanged (596), the activation field model continues to be displayed byuser interface 486 (594).

FIG. 47 is a diagram illustrating a user interface 598 presentingthree-dimensional view of a lead having a complex electrode arraygeometry. Although other embodiments emphasize presentation of two ormore two-dimensional views of a lead with a complex electrode arraygeometry, a three-dimensional representation also may be useful. Userinterface 598 is an embodiment of user interface 98 and programmer 600is an embodiment of programmer 19. In the example of FIG. 30, userinterface 598 of programmer 600 presents an isometric view 602 of thelead to present a virtual three-dimensional view of the lead. Arrows 606or other input media may be provided to permit the user to rotate thethree-dimensional representation of the lead. In particular, userinterface 598 may rotate the lead about its longitudinal axis to showelectrodes on different sides of the lead. As in other embodiments, auser may select electrodes, e.g., with a stylus 608, and specifyparameter values in an electrode view.

Also, the user may select a three-dimensional field view, as shown inFIG. 48. User interface 610 is an embodiment of user interface 98 andsimilar to user interface 598. Programmer 612 is an embodiment ofprogrammer 19 and similar to programmer 600. In the field view, userinterface 610 may allow the field to be manipulated by the user in termsof size, shape, location, or the like, as previously discussed.Programmer 612 responds by selecting electrode combinations, polaritiesand parameter values sufficient to approximate stimulation field 616manipulated by the user. In the three-dimensional electrode view of FIG.47 and the field view of FIG. 48, the three-dimensional representationmay be displayed alone or in combination with other views, such astwo-dimensional views, e.g., a side view a cross-sectional view, aconcentric axial view, or an unwrapped 2D array view. Many othercombinations of three-dimensional and two-dimensional views areconceivable, as well as other three-dimensional views in addition to theillustrated isometric view. Also, orientation markers 604 also may beprovided as shown in FIG. 46 to show the orientation of the electrodesof the lead relative to an anatomical structure.

Although this disclosure has referred to neurostimulation applicationsgenerally, and DBS and SCS applications more particularly, suchapplications have been described for purposes of illustration and shouldnot be considered limiting of the invention as broadly embodied anddescribed herein. The invention may be more generally applicable toelectrical stimulation of tissue, such as nerve tissue or muscle tissue,and may be applicable to a variety of therapy applications includingspinal cord stimulation, pelvic floor stimulation, deep brainstimulation, cortical surface stimulation, neuronal ganglionstimulation, gastric stimulation, peripheral nerve stimulation, orsubcutaneous stimulation. Such therapy applications may be targeted to avariety of disorders such as chronic pain, peripheral vascular disease,angina, headache, tremor, Parkinson's disease, epilepsy, urinary orfecal incontinence, sexual dysfunction, obesity, or gastroparesis. Also,the invention is not necessarily limited to use with completelyimplanted neurostimulators, and may also be applicable to externalstimulators coupled to implanted leads via a percutaneous port.

In addition, although electrode array geometries having four or eightaxial electrode levels and four angular electrode positions have beendescribed, the disclosure may be applicable to a wide variety ofelectrode array geometries including virtually any number of axial andangular electrode positions. Again, a complex electrode array geometrygenerally refers to an arrangement of stimulation electrodes at multiplenon-planar or non-coaxial positions, in contrast to simple electrodearray geometries in which the electrodes share a common plane or acommon axis. An example of a simple electrode array geometry is an arrayof ring electrodes distributed at different axial positions along thelength of a lead. Another example of a simple electrode array geometryis a planar array of electrodes on a paddle lead.

An example of a complex electrode array geometry, in accordance withthis disclosure, is an array of electrodes positioned at different axialpositions along the length of a lead, as well as at different angularpositions about the circumference of the lead. In some embodiments, theelectrodes in the complex array geometry may appear similar tonon-contiguous, arc-like segments of a conventional ring electrode. Alead with a complex electrode array geometry may include multiple ringsof electrode segments. Each axially positioned ring is disposed at adifferent axial position. Each electrode segment within a given ring isdisposed at a different angular position. The lead may be cylindrical orhave a circular cross-section of varying diameter. Another example of acomplex electrode array geometry is an array of electrodes positioned onmultiple planes or faces of a lead. As an illustration, arrays ofelectrodes may be positioned on opposite planes of a paddle lead ormultiple faces of a lead having a polygonal cross-section. Also,electrodes positioned at particular axial or angular positions need notbe aligned with other electrodes. Rather, in some embodiments,electrodes may be arranged in a staggered or checkerboard-like pattern.

Further, although a single lead may be useful in various stimulationapplications, multiple leads may be useful in other applications such asbi-lateral DBS, SCS, or multi-site stimulation for gastric, pelvic orperipheral nerve stimulation. Accordingly, electrode combinations may beformed between electrodes carried by a single lead, electrodecombinations formed between electrodes carried by one lead of a pair ofleads, or electrode combinations formed between electrodes on differentleads, as well as electrodes carried by a stimulator housing, e.g., in aso-called active can configuration.

The techniques described herein may be applied to a programminginterface or control interface associated with a physician programmer, apatient programmer, or both. Hence, a physician may use a physicianprogrammer in clinic to program and evaluate different electrodecombinations and stimulation parameter values. A patient may use apatient programmer during daily use to adjust parameter values, selectdifferent electrode combinations, subject to keepout zones and rangesspecified by the physicians. The physician programmer or patientprogrammer may be a small, portable, handheld device, similar to apersonal digital assistant (PDA). Alternatively, in the case of aphysician programmer, the programmer may be implemented in a generalpurpose desktop or laptop computer, computer workstation, or dedicateddesktop programming unit.

In addition, the programming functionality described in this disclosuremay be used to program an implantable stimulator coupled to one or moreimplantable leads or an external stimulator coupled to one morepercutaneous leads. For example, the invention may be used for trialstimulation or chronic stimulation. In addition, the guided evaluationtechniques provided by programmer 19 may be used in the physicianprogrammer or in the patient programmer. In the case of a patientprogrammer, guided evaluation may automatically select electrodecombinations and stimulation parameters for evaluation by the patientover a period of time, or present such combinations and parameters tothe patient for proposed evaluation.

The patient may enter efficacy feedback into the patient programmer toindicate the perceived efficacy of each electrode combination and set ofparameter values. The feedback may be recorded as efficacy informationin the programmer for later retrieval by the physician to identifyprograms that are most effective for the patient. In addition, thefeedback information may be used to rate different programs and presentthe ratings for selection of programs by the patient.

In some cases, the patient programmer may guide the patient throughdifferent electrode combinations by forcing the patient to evaluate newor unevaluated programs over a period of time. For example, onceevaluated, a program (including electrode combination and parametervalues) may be hidden from view or locked out so that the patient cannotreevaluate the same program. This encourages the patient to continuetrying new stimulation options.

The physician programmer, patient programmer or both may include theability to present both an electrode view for manual selection ofelectrodes and parameter values, and a field view for manipulation ofstimulation field size, position or shape followed by automaticprogramming of electrode combination and parameter values to approximatethe desired stimulation field. The stimulation field may be defined bythe selected stimulation parameters in the electrode view or byoutlining and defining the stimulation field first. The stimulationfield may be manipulated by a variety of input media, including softkeys, touchscreen keys, hard keys, scroll wheels, touchpad's, joysticks,a mouse, a trackball, or other devices.

In general, such input devices may be used to provide different viewingperspectives (side, cross-sectional, concentric axial, and unwrapped 2Darray) of a lead with complex electrode array geometry, and permitrotation of the perspective views to observe sides of the lead that maynot be visible in a single two-dimensional side view. Other perspectiveview, independent or in conjunction with axial and cross-sectionalviews, are possible. Fore example, skewed views looking down the lengthof the lead from above are possible. In addition, views showing bothsides of a lead are possible.

The disclosure also contemplates computer-readable media comprisinginstructions to cause a processor to perform any of the functionsdescribed herein. The computer-readable media may take the form of anyvolatile, non-volatile, magnetic, optical, or electrical media, such asa random access memory (RAM), read-only memory (ROM), non-volatile RAM(NVRAM), electrically-erasable programmable ROM (EEPROM), flash memory,or any other digital media.

Various embodiments of the invention have been described. These andother embodiments are within the scope of the following claims.

What is claimed is:
 1. A method comprising: presenting, at a display, anunwrapped two-dimensional (2D) array view of a representation of animplantable lead having a complex electrode array geometry, wherein theimplantable lead comprises a plurality of non-contiguous electrodesegments located at different angular positions about a circumference ofthe lead, and the unwrapped 2D array view depicts each of the electrodesegments.
 2. The method of claim 1, wherein the plurality ofnon-contiguous electrode segments comprises a first level ofnon-contiguous electrode segments located at a first axial positionalong the length of the implantable lead and a second level ofnon-contiguous electrode segments located at a second axial positionalong the length of the implantable lead, and wherein the electrodesegments of the first level are staggered at different angular positionsfrom the electrode segments of the second level.
 3. The method of claim1, wherein the plurality of non-contiguous electrode segments comprisesa first level of non-contiguous electrode segments located at a firstaxial position along the length of the implantable lead and a secondlevel of non-contiguous electrode segments located at a second axialposition along the length of the implantable lead, and wherein theelectrode segments of the first level are aligned at the same angularpositions as the electrode segments of the second level.
 4. The methodof claim 1, further comprising presenting, at the display and inconjunction with the unwrapped 2D array view, a representation of astimulation field produced by a set of electrodes on the lead, whereinthe set of electrodes corresponds to a selected subset of the pluralityof non-contiguous electrode segments.
 5. The method of claim 4, whereinthe stimulation field comprises an electrical field that illustrates anarea of propagation of an electrical field produced by the set ofelectrodes through tissue adjacent to the implantable lead.
 6. Themethod of claim 4, wherein the stimulation field comprises an activationfield that indicates a set of neurons activated by an electrical fieldthat propagates through tissue from the set of electrodes on the lead,wherein the method further comprises generating the activation fieldbased on a neuron model.
 7. The method of claim 4, further comprising:receiving, via interaction with the unwrapped 2D array view, user inputdefining the stimulation field; and selecting, by a processor and basedon the user input, at least one of an electrode combination and one ormore stimulation parameter values to approximate the defined stimulationfield, wherein electrical stimulation therapy is at least partiallydefined by the electrode combination and the one or more stimulationparameter values.
 8. The method of claim 7, further comprisingdelivering stimulation energy via the electrode combination of the leadand based on the one or more stimulation parameter values to provide atleast one of deep brain stimulation, spinal cord stimulation, pelvicnerve stimulation, gastric nerve stimulation, peripheral nervestimulation, or muscle stimulation.
 9. A system comprising: a display;and one or more processors configured to present, at the display, anunwrapped two-dimensional (2D) array view of a representation of animplantable lead having a complex electrode array geometry, wherein theimplantable lead comprises a plurality of non-contiguous electrodesegments located at different angular positions about a circumference ofthe lead, and the unwrapped 2D array view depicts each of the electrodesegments.
 10. The system of claim 9, wherein the plurality ofnon-contiguous electrode segments comprises a first level ofnon-contiguous electrode segments located at a first axial positionalong the length of the implantable lead and a second level ofnon-contiguous electrode segments located at a second axial positionalong the length of the implantable lead, and wherein the electrodesegments of the first level are staggered at different angular positionsfrom the electrode segments of the second level.
 11. The system of claim9, wherein the plurality of non-contiguous electrode segments comprisesa first level of non-contiguous electrode segments located at a firstaxial position along the length of the implantable lead and a secondlevel of non-contiguous electrode segments located at a second axialposition along the length of the implantable lead, and wherein theelectrode segments of the first level are aligned at the same angularpositions as the electrode segments of the second level.
 12. The systemof claim 9, wherein the one or more processors are configured topresent, at the display and in conjunction with the unwrapped 2D arrayview, a representation of a stimulation field produced by a set ofelectrodes on the lead, wherein the set of electrodes corresponds to aselected subset of the plurality of non-contiguous electrode segments.13. The system of claim 12, wherein the stimulation field comprises anelectrical field that illustrates an area of propagation of anelectrical field produced by the set of electrodes through tissueadjacent to the implantable lead.
 14. The system of claim 12, whereinthe stimulation field comprises an activation field that indicates a setof neurons activated by an electrical field that propagates throughtissue from the set of electrodes on the lead, wherein the one or moreprocessors are configured to generate the activation field based on aneuron model.
 15. The system of claim 12, further comprising a userinterface configured to receive, via interaction with the unwrapped 2Darray view, user input defining the stimulation field, wherein the oneor more processors are configured to select, based on the user input, atleast one of an electrode combination and one or more stimulationparameter values to approximate the defined stimulation field, whereinelectrical stimulation therapy is at least partially defined by theelectrode combination and the one or more stimulation parameter values.16. The system of claim 15, further comprising transmitting theelectrode combination and the one or more stimulation parameter valuesto a medical device configured to deliver stimulation energy via theelectrode combination of the lead and based on the one or morestimulation parameter values to provide at least one of deep brainstimulation, spinal cord stimulation, pelvic nerve stimulation, gastricnerve stimulation, peripheral nerve stimulation, or muscle stimulation.17. A system comprising: means for presenting an unwrappedtwo-dimensional (2D) array view of a representation of an implantablelead having a complex electrode array geometry, wherein the implantablelead comprises a plurality of non-contiguous electrode segments locatedat different angular positions about a circumference of the lead, andthe unwrapped 2D array view depicts each of the electrode segments. 18.The system of claim 17, wherein the plurality of non-contiguouselectrode segments comprises a first level of non-contiguous electrodesegments located at a first axial position along the length of theimplantable lead and a second level of non-contiguous electrode segmentslocated at a second axial position along the length of the implantablelead, and wherein the electrode segments of the first level arestaggered at different angular positions from the electrode segments ofthe second level.
 19. The system of claim 17, wherein the plurality ofnon-contiguous electrode segments comprises a first level ofnon-contiguous electrode segments located at a first axial positionalong the length of the implantable lead and a second level ofnon-contiguous electrode segments located at a second axial positionalong the length of the implantable lead, and wherein the electrodesegments of the first level are aligned at the same angular positions asthe electrode segments of the second level.
 20. The system of claim 17,further comprising: means for presenting, in conjunction with theunwrapped 2D array view, a representation of an activation fieldproduced by a set of electrodes on the lead, wherein the set ofelectrodes corresponds to a selected subset of the plurality ofnon-contiguous electrode segments, and wherein the activation fieldindicates a set of neurons activated by an electrical field thatpropagates through tissue from the set of electrodes on the lead; meansfor generating the activation field based on a neuron model; means forreceiving, via interaction with the unwrapped 2D array view, user inputdefining the activation field; and means for selecting, based on theuser input, at least one of an electrode combination and one or morestimulation parameter values to approximate the defined activationfield, wherein electrical stimulation therapy is at least partiallydefined by the electrode combination and the one or more stimulationparameter values.